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2000 data sheet lsi devices for inter equipment bus tm (iebus tm ) protocol control mos integrated circuit m pD72042 the m pD72042 is a microcomputer peripheral lsi device for iebus protocol control. the m pD72042 performs all the processing required for layers 1 and 2 of the iebus. the devices incorporate large transmission and reception buffers, allowing the microcomputer to perform iebus operations without interruption. they also contain an iebus driver and receiver, allowing them to directly connected to the bus directly. features ? ? control of layers 1 and 2 of the iebus protocol ? support of a multi-master scheme ? broadcast function ? two communication modes having different transmission speeds can be selected. ? ? microcomputer interface three-/two-wire serial i/o, transfer starting with msb ? ? program crashes can be detected by means of a watchdog timer. ? ? low power consumption (standby mode): 50 m a (max) ? ? oscillator frequency (f x ): 6 mhz ? frequency accuracy: 1.5% ? ? operating voltage: 5 v 10% document no. s14870ej1v0ds00 (1st edition) date published june 2000 n cp(n) printed in japan l l built-in iebus driver and receiver l l transmission and reception buffers transmission buffer : 33 bytes, fifo reception buffer : 40 bytes, fifo (capable of holding more than one frame of reception data.) ordering information part number package m pD72042gt 16-pin plastic sop (9.53 mm (375)) transmission speed mode 0 approx. 3.9 kbps mode 1 approx. 17 kbps the information in this document is subject to change without notice. before using this document, please confirm that this is the latest version. not all devices/types available in every country. please check with local nec representative for availability and additional information. www.datasheet.in
m pD72042 2 data sheet s14870ej1v0ds00 pin configuration (top view) ? 16-pin plastic sop (9.53 mm (375)) m pD72042gt note parentheses indicate the state corresponding to two-wire serial i/o mode. av dd : main power supply for iebus (connected to the v dd pin) busC, bus+ : iebus i/o c/d : command/data switch input cs : chip select input gnd : ground irq : interrupt request output nc : no connection reset : reset input sck : serial clock input sel : serial mode selection si : serial data input sio : serial data i/o so : serial data output test : test input (connected to the v dd pin) v dd : main power supply xi, xo : system clock 1 2 3 4 5 6 7 8 v dd test reset cs sel av dd bus + bus - 16 15 14 13 12 11 10 9 sck si(sio) note so(nc) note irq c/d xi xo gnd www.datasheet.in
m pD72042 3 data sheet s14870ej1v0ds00 block diagram remark the pin names in parentheses are used when two-wire serial i/o is selected. bus + bus xi xo ctr cmr tbf (33 bytes) str flg rbf (40 bytes) test reset av dd v dd gnd irq sel so (nc) si (sio) sck c/d cs data link controller oscillation control section program crash detection section internal bus receiver driver filter p/s conversion section serial i/o control section contention detection section parity generation section parity detection section synchronization control section test circuit timing generation section frame data control section rdb (7 bytes) wdb (5 bytes) www.datasheet.in
m pD72042 4 data sheet s14870ej1v0ds00 contents 1. pin functions ............................................................................................................................ 6 1.1 pin functions ............................................................................................................................... .... 6 2. iebus operation ....................................................................................................................... 8 2.1 overview ............................................................................................................................... ............... 8 2.2 iebus communication protocol .............................................................................................. 9 2.2.1 bus mastership determination (arbitration) ............................................................................... 10 2.2.2 communication mode ................................................................................................................. 10 2.2.3 communication address ............................................................................................................. 11 2.2.4 broadcast ............................................................................................................................... ...... 11 2.3 transmission protocol .............................................................................................................. 11 2.4 transmission data (contents of the data field) ........................................................ 17 2.5 bit format ............................................................................................................................... ........... 21 3. microcomputer interface ................................................................................................. 22 3.1 transfer method ........................................................................................................................... 22 3.2 data transfer format ................................................................................................................ 23 3.2.1 three-wire data transfer (sel = 1) .......................................................................................... 23 3.2.2 two-wire data transfer (sel = 0) ............................................................................................. 25 3.3 connection to a microcomputer ......................................................................................... 27 3.4 standby mode setting and cancellation ....................................................................... 28 3.5 reset mode setting and cancellation ............................................................................ 28 4. registers ............................................................................................................................... ..... 29 5. example timings for communication .......................................................................... 59 6. example microcomputer processing flow ............................................................. 67 6.1 communication flags ................................................................................................................... 68 6.2 main routine ............................................................................................................................... ...... 69 6.3 interrupt routine ......................................................................................................................... 70 6.4 processing routines .................................................................................................................... 72 6.4.1 m pD72042 initial setting routine ............................................................................................... 72 6.4.2 communication flag initialization routine ................................................................................. 72 6.4.3 command processing routine ................................................................................................... 73 6.4.4 master communication processing routine .............................................................................. 73 6.4.5 slave data transmission processing routine ........................................................................... 77 6.4.6 transmission processing routine .............................................................................................. 80 6.4.7 reception processing routine ................................................................................................... 81 7. electrical characteristics ............................................................................................. 82 8. package drawing .................................................................................................................... 86 www.datasheet.in
m pD72042 5 data sheet s14870ej1v0ds00 9. recommended soldering conditions ........................................................................... 87 appendix a main differences between m pD72042, m pD72042b, and m pd6708 ..... 88 appendix b iebus protocol analyzer ................................................................................ 88 www.datasheet.in
m pD72042 6 data sheet s14870ej1v0ds00 1. pin functions 1.1 pin functions pin no. 1 2 3 4 5 6 7 8 9 10 11 12 13 pin note sck si (sio) so (nc) irq c/d xi xo gnd busC bus+ av dd sel cs i/o note input input (i/o) output (none) output input C C i/o C input input function serial clock input pin for cpu interface serial data pin for cpu interface. (this pin functions as an input pin when 3-wire serial i/o mode is selected, or as an i/o pin when 2-wire serial i/o mode is selected.) serial data output pin for cpu interface. (the pin functions as an output when 3-wire serial i/o mode is selected. when 2-wire serial i/o mode is selected, the pin is left open.) output pin for making an interrupt request to the cpu. when a return code or a program crash is detected, a high-level signal is output on this pin for at least 8 m s. input pin used to select control mode or data read/write mode. when this pin is driven high, internal register address setting and data read/ write are enabled. when the mode changes, the serial clock counter is reset. pins for connecting a system clock resonator. a 6-mhz crystal or ceramic resonator must be used. the accuracy of the frequency is as follows; mode 0, 1: 1.5% ground pin i/o pins connected to the iebus bus main power supply pin for the iebus bus driver/ receiver. when used, this pin must be tied to v dd . input pin used to select either 3- or 2-wire serial i/o mode. a high-level signal on this pin selects 3-wire serial i/o mode. a low-level signal on this pin selects 2-wire serial i/o mode. chip select pin. when this pin is driven low, the serial interface is enabled. when this pin is driven high, the so pin becomes high-imped- ance, and the serial clock counter is reset. when reset [for both hardware and software] input input high-impedance low level input when reset by hardware (oscil- lation stopped) xi = gnd xo = high level when reset by software (oscil- lation continued) C high-impedance C input input i/o format note cmos input cmos input (cmos i/o) cmos output (none) cmos output cmos input C C C C cmos input cmos input note parentheses indicate the state corresponding to two-wire serial i/o mode. www.datasheet.in
m pD72042 7 data sheet s14870ej1v0ds00 pin no. 14 15 16 pin reset test v dd i/o input input C function serial reset signal input pin. a low input causes a reset. whenever the power is turned on, a low-level signal must be applied to this pin. during normal operation, a high level is applied. ic test pin. when used, this pin must be tied to the v dd pin directly. main power supply input pin when reset [for both hardware and software] input C C i/o format cmos input cmos input C www.datasheet.in
m pD72042 8 data sheet s14870ej1v0ds00 2. iebus operation 2.1 overview the m pD72042 is a cmos lsi device for the iebus interface. the iebus is designed to enable the data transmission between devices in a small-scale digital data transmission system. the m pD72042 is connected to a microcomputer built into a device. a serial interface (sck, so, and si pins) is used for connection. the host controller (microcomputer) sets the commands and data needed for data transmission via this serial interface. when data is transmitted, the host controller sets the data in the m pD72042 via the serial interface. then, signals are output on the bus pins (bus+, busC). when data is received from the bus pins, the host controller can read it via the serial interface. www.datasheet.in
m pD72042 9 data sheet s14870ej1v0ds00 2.2 iebus communication protocol the iebus is outlined below. ? communication method: half duplex asynchronous communication ? multi-master method all units connected to the iebus can transmit data to every other connected unit. ? broadcast function (one-unit-to-multiple-units communication) group broadcast : broadcast to a specific group of units general broadcast : broadcast to all units ? two modes, each offering different transmission speeds, can be selected. maximum number of bytes transmitted (bytes/frame) mode 0 approx. 3.9 kbps 16 mode 1 approx. 17 kbps 32 transmission speed ? access control: carrier sense multiple access with collision detection (csma/cd) bus mastership priority is as follows: 1 broadcast takes priority over ordinary communication (one-unit-to-one-unit communication). 2 units having lower master addresses have a higher priority. ? communication scale number of units : 50 max cable length : 150 m max (when twisted-pair cable is used ) load capacity : 7000 pf max terminating resistance : 120 w www.datasheet.in
m pD72042 10 data sheet s14870ej1v0ds00 2.2.1 bus mastership determination (arbitration) before devices connected to the iebus can control other devices, they must first acquire the bus. this operation is called arbitration. when more than one unit starts transmission at the same time, arbitration determines which of those units is allowed to use the bus. when arbitration results in only one device being granted bus mastership, the following bus mastership priority conditions are used: remark those devices that are defeated in arbitration can automatically enter retransmission mode. (for the m pD72042, the number of retransmissions can be set by specifying a value between 0 and 7 in the mcr register.) (1) priority by communication type broadcast (one-unit-to-multiple-units communication) takes priority over ordinary communication (one-unit-to- one-unit communication). (2) priority by master address if the communication type is the same, the smallest master address value has the highest priority. example each master address consists of 12 bits. a unit having master address 000h has the highest priority, while a unit having master address fffh has the lowest priority. 2.2.2 communication mode the iebus supports two communication modes, each having a different transmission speed. table 2-1 lists the transmission speed for each communication mode and the maximum number of bytes transmitted within one communication frame. table 2-1 transmission speed and maximum number of transmission bytes in each communication mode communication mode maximum number of transmission effective transmission speed (kbps) bytes (bytes/frame) 0 16 approx. 3.9 1 32 approx. 17 note effective transmission speed at which the maximum transfer rate is achieved caution before devices connected to the iebus can perform communication, an appropriate commun- ication mode must be set. note that if a master unit and an associated unit (slave unit) have different communication modes, they will not be able to communicate properly. note www.datasheet.in
m pD72042 11 data sheet s14870ej1v0ds00 2.2.3 communication address with the iebus, each device is assigned a unique 12-bit communication address. the communication address consists of the following parts: high-order 4 bits : group number (number identifying the group to which a device belongs) low-order 8 bits : unit number (number identifying a device in a group) 2.2.4 broadcast in ordinary communication, transmission and reception are performed between one master unit and one associated slave unit. broadcast can also be done between one master unit and more than one slave unit. in this case master unit transmits data to an arbitrary number of slave units. in this case, the slave units do not return on acknowledge signal to the master unit. whether the communication to be performed is broadcast or ordinary communication is determined by the setting of the broadcast bit. (for details of the broadcast bit, see (1) 2 in section 2.3 .) there are two types of broadcast. (1) group broadcast broadcast is performed to the devices in a particular group. these devices all have the same group number, as indicated by the high-order 4 bits of each communication address. (2) general broadcast broadcast is performed to all devices, regardless of their group numbers. these two types of broadcast are distinguished by the slave address. (for details of the slave address, see (3) in section 2.3 .) 2.3 transmission protocol fig. 2-1 shows the iebus transmission signal format. communication data is transmitted as a sequence of signals called a communication frame. the transmission speed and the maximum amount of data that can be transmitted in one communication frame depend on the communication mode. www.datasheet.in
m pD72042 12 data sheet s14870ej1v0ds00 fig. 2-1 transmission signal format p : parity bit (1 bit) a : acknowledge bit (1 bit) when a = 0: ack when a = 1: nak n : number of data bytes remark for broadcast, the value of the acknowledge bit is ignored. (1) header the header consists of a start bit and a broadcast bit. these are explained below. 1 start bit the start bit is a signal used to notify the other units of the beginning of data transmission. before a unit starts data transmission, it outputs a low-level signal (start bit) for a specified duration, then outputs the broadcast bit. when the unit attempts to output the start bit, another unit may have already output the start bit. in such a case, the unit does not output the start bit, and instead waits for the other unit to stop outputting the start bit. then, synchronized with the completion of start bit output by the other unit, the unit starts output of the broadcast bit. all units, except that unit which started the transmission, detect the start bit and become ready for reception. 2 broadcast bit the broadcast bit is used to distinguish between broadcast and ordinary communication. if the broadcast bit is 0, broadcast is indicated. if the broadcast bit is 1, ordinary communication is indicated. there are two types of broadcast: group broadcast and general broadcast. these types are distinguished by the slave address. (for details of the slave address, see (3) .) for broadcast, more than one slave unit can exist as an associated communication station. therefore, the acknowledge bits for the master address field and subsequent fields are not returned. when more than one unit starts sending a communication frame at the same time, broadcast takes precedence over ordinary communication and wins arbitration. field name number of bits header 11 master address field 12 1 slave address field 12 1 1 control field 411 data-length field 811 data field 811 811 start bit broad- cast bit master address p slave address p a control bits pa data- length bits p a data bits p a data bits pa transmission time mode 0 mode 1 approx. 7330 approx. 2090 approx. 1590 n approx. 410 n m s m s m s m s www.datasheet.in
m pD72042 13 data sheet s14870ej1v0ds00 (2) master address field the master address field is used to transmit the local unit address (master address) to other units. the master address field consists of master address bits and a parity bit. a master address consists of 12 bits. it is output starting with the msb. when more than one unit starts transmitting the same broadcast bit value at the same time, arbitration determination is performed by the master address field. each time a unit transmits one bit of the master address field, the unit compares its output data with the data on the bus. if the comparison indicates that the master address output by the unit differs from the data on the bus, the unit determines that it has lost an arbitration. the unit stops transmission, and readies itself for reception. the iebus is organized by wired and. when arbitration is performed between units (arbitration masters), the unit having the smallest master address value wins the arbitration. after the 12-bit master address has been output, only one unit is finally determined as being the master unit, such that that unit remains in the transmission state. next, the master unit outputs a parity bit note to post the master address to other units. then, the master unit proceeds to the slave address field. note even parity is used. when the number of 1s in the master address bits is odd, the parity bit is set to 1. (3) slave address field the slave address field is used to transmit the address (slave address) of a unit (slave unit) with which the master unit wants to communicate. the slave address field consists of slave address bits, a parity bit, and an acknowledge bit. a slave address consists of 12 bits. it is output starting with the msb. after a 12-bit slave address has been transmitted, a parity bit is output to prevent the slave address from being received incorrectly. then, the master unit attempts to detect the acknowledge signal from a slave unit to confirm that the slave unit exists on the bus. when the acknowledge signal is detected, the master unit outputs a control field. note, however, that when performing broadcast, the master unit outputs the control field without attempting to detect the acknowledge bit. the slave unit outputs an acknowledge signal when the slave unit recognizes a match between the slave units address and the slave address transmitted by the master unit match, and that both the master address and slave address have even parity. if the slave unit detects odd parity, it does not recognize the addresses as matching, so does not output an acknowledge signal. in this case, the master unit is placed in the standby (monitor) state, and communication terminates. for broadcast, the slave address is used to distinguish between group broadcast or general broadcast, as follows: when the slave address is fffh : general broadcast when the slave address is other than fffh : group broadcast remark for group broadcast, the number of a target group is indicated by the high-order 4 bits of the slave address. www.datasheet.in
m pD72042 14 data sheet s14870ej1v0ds00 (4) control field the control field indicates the type and direction of the next data field. the control field consists of control bits, a parity bit, and an acknowledge bit. the four control bits are output starting with the msb. following the control bits, a parity bit is output. if even parity is detected, and the function requested by the master unit can be performed by the slave unit, the slave unit outputs an acknowledge signal. then, the slave unit proceeds to the data-length field. if the slave unit cannot perform the processing requested by the master unit, even when even parity is detected, or if odd parity is detected, the slave unit does not output an acknowledge signal, and it enters the standby (monitor) state again. after detecting the acknowledge signal, the master unit proceeds to the data-length field. if an acknowledge signal is not detected, the master unit enters the standby state, terminating communication. for broadcast, however, the master unit proceeds to the next data-length field without attempting to detect the acknowledge signal. table 2-3 lists the meanings of the control bits. (5) data-length field the data-length field specifies the communication data length, in bytes. the data-length field consists of the data-length bits, a parity bit, and an acknowledge bit. the eight data-length bits are output starting with the msb. the data-length bits indicate the communication data length, in bytes, as shown in table 2-2. table 2-2 values of the data-length bits and their meanings data-length bit (hexadecimal) transmission data length, in bytes 01h 1 02h 2 :: :: ffh 255 00h 256 remark if the data length set in the data-length bits exceeds the maximum number of transmission bytes, the latter varying with the communication mode, more than one frame is transmitted. in the second and subsequent frames, the data-length bits indicate the remaining communication data length, in bytes. the operation performed for this field differs depending on whether master transmission (when bit 3 of the control bits is 1) or master reception (when bit 3 of the control bits is 0) is performed. 1 master transmission the data-length bits and parity bit are output by the master unit. when the slave unit detects even parity, the slave unit outputs an acknowledge signal, then proceeds to the data field. for broadcast, however, the slave unit does not output an acknowledge signal. if the slave unit detects odd parity, the slave unit does not output an acknowledge signal, regarding the received data-length bits as being incorrect. then, the slave unit enters the standby (monitor) state again. at this time, the master unit also enters the standby state again, and communication terminates. www.datasheet.in
m pD72042 15 data sheet s14870ej1v0ds00 2 master reception the data-length bits and parity bit are output by the slave unit. when the master unit detects even parity, the master unit outputs the acknowledge signal. if the master unit detects odd parity, the master unit does not output an acknowledge signal, regarding the received data-length bits as being incorrect. then, the master unit enters the standby state again. at this time, the slave unit also enters the standby state again, and communication terminates. (6) data field the data field is used for data transmission and reception to and from a slave unit. the master unit uses the data field to transmit data to the slave unit, or to receive data from the slave unit. the data field consists of data bits, a parity bit, and an acknowledge bit. the eight data bits are output, starting with the msb. after the data bits have been output, the parity bit and acknowledge bit are output from the master unit and slave unit, respectively. broadcast is performed only when the master unit transmits data. at this time, any acknowledge signal is ignored. the operations related to master transmission and master reception are explained below. 1 master transmission when the master unit performs a write to a slave unit, the master unit transmits the data bits and a parity bit to the slave unit. the slave unit receives the data bits and parity bit, then outputs an acknowledge signal if even parity is detected and the reception buffer is empty. if odd parity is detected, or if the reception buffer is not empty, the slave unit rejects the corresponding data, and does not output an acknowledge signal. if no acknowledge signal is received from the slave unit, the master unit transmits the same data again. the master unit repeats this operation until it receives an acknowledge signal from the slave unit, or until the data exceeds the maximum number of transmission bytes. when even parity is detected, and an acknowledge signal is received from the slave unit, the master unit transmits the subsequent data, if any, and provided the maximum number of transmission bytes is not reached. for broadcast, an acknowledge signal is not output by any slave unit. the master unit transfers data one byte at a time. 2 master reception when the master unit reads data from a slave unit, the master unit outputs a synchronization signal for each bit as it is read. the slave unit outputs data and a parity bit to the bus according to the synchronization signal output by the master unit. the master unit reads the data and parity bit output by the slave unit, and checks the parity. if the master unit detects odd parity, or if the reception buffer is not empty, the master unit rejects the data, and does not output an acknowledge signal. the master unit repeats the read operation for the same data provided the maximum allowable number of transmission bytes per communication frame has not been reached. if the master unit confirms even parity, and the reception buffer is empty, the master unit accepts the data, and returns an acknowledge signal to the slave unit. then, the master unit reads the next data, provided the maximum allowable number of transmission bytes per frame has not been reached. www.datasheet.in
m pD72042 16 data sheet s14870ej1v0ds00 (7) parity bit a parity bit is used to check for errors in the transmission data. a parity bit is added to the master address bits, slave address bits, control bits, data-length bits, and data bits. even parity is used. if the number of 1s in the data is odd, the parity bit is set to 1. if the number of 1s in the data is even, the parity bit is set to 0. (8) acknowledge bit in ordinary communication (one-unit-to-one-unit communication), an acknowledge bit is added in the following positions to confirm that data has been received correctly: ? at the end of the slave address field ? at the end of the control field ? at the end of the data-length field ? at the end of the data field the acknowledge bit is defined as follows: ? 0: indicates that transmission data has been recognized. (ack) ? 1: indicates that no transmission data has been recognized. (nak) for broadcast, the acknowledge bit is ignored. 1 acknowledge bit at the end of the slave address field if any of the following is detected, the acknowledge bit at the end of the slave address field is set to nak, and transmission is stopped: ? the parity of the master address bits or slave address bits is incorrect. ? a timing error occurred (bit format error). ? no slave unit is found. 2 acknowledge bit at the end of the control field if any of the following is detected, the acknowledge bit at the end of the control field is set to nak, and transmission is stopped: ? the parity of the control bits is incorrect. ? although the slave reception buffer note is not empty, bit 3 of the control bits is 1 (write operation). ? although the slave transmission buffer note is empty, the control bits indicate data read (3h, 7h). ? for a locked unit, a unit other than the unit that specified the lock makes a request by using control bits indicating 3h, 6h, 7h, ah, bh, eh, or fh. ? although no lock has been set, control bits indicating lock address read (4h) are set. ? a timing error occurred. ? an undefined control bit setting has been made. note see (1) in section 2.4 . www.datasheet.in
m pD72042 17 data sheet s14870ej1v0ds00 3 acknowledge bit at the end of the data-length field if any of the following is detected, the acknowledge bit at the end of the data-length field is set to nak, and transmission is stopped: ? the parity of the data-length bits is incorrect. ? a timing error occurred. 4 acknowledge bit at the end of the data field if any of the following is detected, the acknowledge bit at the end of the data field is set to nak, and transmission is stopped: ? the parity of the data bits is incorrect note . ? a timing error occurred after the previous acknowledge bit. ? the reception buffer is full, such that no more data can be accepted note . note in this case, if the maximum allowable number of transmission bytes per frame has not yet been reached, the transmitter retries transmission of the data field until the maximum number of transmission bytes is reached. 2.4 transmission data (contents of the data field) the contents of the data field are indicated by the control bits. www.datasheet.in
m pD72042 18 data sheet s14870ej1v0ds00 table 2-3 meanings of the control bits bit 3 note 1 bit 2 bit 1 bit 0 function note 2 0h 0 0 0 0 read slave status (ssr) 1h 0 0 0 1 undefined 2h 0 0 1 0 undefined 3h 0 0 1 1 read data and locking 4h 0 1 0 0 read lock address (low-order 8 bits) 5h 0 1 0 1 read lock address (high-order 4 bits) 6h 0 1 1 0 read slave status (ssr) and unlocking 7h 0 1 1 1 read data 8h 1 0 0 0 undefined 9h 1 0 0 1 undefined ah 1 0 1 0 write command and locking bh 1 0 1 1 write data and locking ch 1 1 0 0 undefined dh 1 1 0 1 undefined eh 1 1 1 0 write command fh 1 1 1 1 write data notes 1. the transfer direction of the data-length bits of the subsequent data-length field and data in the data field changes according to the value of bit 3 (msb). when bit 3 is 1: transfer from the master unit to the slave unit when bit 3 is 0: transfer from the slave unit to the master unit 2. the values of control bits 3h, 6h, ah, and bh specify locking and unlocking. when an undefined value, 1h, 2h, 8h, 9h, ch, or dh, is transmitted, no acknowledge signal is returned. once a unit has been locked by a master unit, the locked unit rejects the control bits received from other than the master unit that requested the lock, unless the value of the control bits is one of the values listed in table 2-4. then, the unit does not output the acknowledge bit. table 2-4 control field acceptable to a locked slave unit bit 3 bit 2 bit 1 bit 0 function 0h 0 0 0 0 read slave status 4h 0 1 0 0 read lock address (low-order 8 bits) 5h 0 1 0 1 read lock address (high-order 4 bits) (1) reading the slave status (ssr) (control bits: 0h, 6h) a master unit can read the slave status (0h, 6h) to determine why the slave unit did not return the acknowledge bit (ack). the slave status is determined from the result of the communication last performed by the slave unit. all slave units can provide slave status information. table 2-5 lists the slave status meanings. www.datasheet.in
m pD72042 19 data sheet s14870ej1v0ds00 fig. 2-2 slave status (ssr) bit format table 2-5 slave status meanings bit value meaning bit 0 note 1 0 the slave transmission buffer is empty. 1 the slave transmission buffer is not empty. bit 1 note 2 0 the slave reception buffer is empty. 1 the slave reception buffer is not empty. bit 2 0 the unit is not locked. 1 the unit is locked. bit 3 0 fixed at 0 bit 4 note 3 0 slave transmission disabled 1 slave transmission enabled bit 5 0 fixed at 0 bit 7 00 mode 0 bit 6 01 mode 1 10 reserved for future expansion 11 indicates the highest mode supported by the unit note 4 . notes 1. the slave transmission buffer is accessed during a data read operation (control bits: 3h, 7h). for the m pD72042, this buffer corresponds to the tbf available when strq of the flg register is set to 1. 2. the slave reception buffer is accessed during a data write operation (control bits: 8h, ah, bh, eh, fh). for the m pD72042, this buffer corresponds to the rbf available when slre of the flg register is set to 1. 3. the value of bit 4 can be selected by using the uar1 register. 4. bits 7 and 6 are currently fixed to 10 in the hardware of the m pD72042. (2) data/command transfer (control bits: read (3h, 7h), write (ah, bh, eh, fh)) when data read (3h, 7h) is set, the data in the data buffer of the slave unit is read into the master unit. when data write (bh, fh) or command write (ah, eh) is set, the data received by the slave unit is processed according to the operation specifications for the slave unit. remarks 1. the user can select data and commands as necessary according to the system. 2. 3h, ah, and bh may cause locking, depending on the communication conditions and status. msb bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 lsb www.datasheet.in
m pD72042 20 data sheet s14870ej1v0ds00 (3) reading a lock address (control bits: 4h, 5h) when a lock address read operation (4h, 5h) is specified, the address (12 bits) of the master unit that issued the lock instruction is read in one-byte form, as shown below. fig. 2-3 lock address format (4) locking and unlocking (control bits: locking (3h, ah, bh), unlocking (6h)) the lock function is used to enable the transfer a message using more than one communication frame. when locked, a unit cannot receive data from other than the unit that requested the lock. locking and unlocking are performed as follows: 1 locking the master unit can lock the slave unit by specifying the lock with the corresponding control bits (3h, ah, bh). in this case, when the transmission or reception of acknowledge bit 0 for the data-length field has been completed, but the communication frame is then terminated before transmission or reception of as many data bytes as are specified by the data-length bits is completed, the slave unit is locked. at this time, the bit indicating the lock status (bit 2) in the slave status byte is set to 1. 2 unlocking the master unit can unlock a locked slave unit when the control bits specify locking (3h, ah, or bh) or unlocking (6h). the slave unit is unlocked once as many data bytes as are specified by the data-length bits have been transmitted or received within one communication frame. at this time, the bit indicating the lock status (bit 2) in the slave status byte is reset to 0. for broadcast, locking or unlocking is not performed. caution when a locked unit is to be unlocked by the unit itself, hardware reset or software reset must be performed. (the lock status can be checked by referring to the contents of the lor2 register.) msb lsb control bits : 4h control bits : 5h low-order 8 bits undefined high-order 4 bits www.datasheet.in
m pD72042 21 data sheet s14870ej1v0ds00 2.5 bit format fig. 2-4 illustrates the bits that constitute an iebus communication frame. fig. 2-4 iebus bit format (concept) preparation period : first and subsequent low-level (logic 1) periods synchronization period : next high-level (logic 0) period data period : period in which a bit value is indicated (logic 1 = low level, logic 0 = high level) the synchronization and data periods are almost equal in duration. for the iebus, synchronization is established for each bit. the specifications of the total time required for a bit and the duration of each period allotted within the bit vary depending on the type of the transmission bits, and whether the unit is a master or slave. logic "1" logic "0" preparation period synchronization period data period preparation period synchronization period data period logic 1: the potential difference between the bus lines (the bus+ and bus- pins) is 20 mv or less (low level). logic 0: the potential difference between the bus lines (the bus+ and bus- pins) is 120 mv or more (high level). www.datasheet.in
m pD72042 22 data sheet s14870ej1v0ds00 3. microcomputer interface 3.1 transfer method either of two microcomputer interface modes can be selected: three-wire serial i/o mode or two-wire serial i/o mode. whether three-wire serial i/o mode or two-wire serial i/o mode is selected depends on the input level of the sel pin (pin 12). (see section 3.3 for details.) sel ? 1: three-wire serial i/o sel ? 0: two-wire serial i/o (1) three-wire serial i/o (sel ? 1) three wires are used to read and write data. the three wires are the serial clock input (sck), serial data input (si note 1 ), and serial data output (so note 2 ). (a) read operation data is output to the so pin upon detecting the falling edge of the sck pin. (b) write operation data is input via the si pin upon detecting the rising edge of the sck pin. at this time, 1 is output on the so pin. (2) two-wire serial i/o (sel ? 0) two wires are used to read and write data. the two wires are the serial clock input (sck) and serial data i/o (sio note 1 ). (a) read operation the sio pin is placed in the output state, and data is output upon detecting the falling edge of the sck pin. (b) write operation the sio pin is placed in the input state, and data is input upon detecting the rising edge of the sck pin. notes 1. the si pin for three-wire serial i/o mode is also used as the sio pin for two-wire serial i/o mode. 2. the impedance of the so pin for three-wire serial i/o mode goes high in two-wire serial i/o mode. so, connect the so pin to gnd or v dd . www.datasheet.in
m pD72042 23 data sheet s14870ej1v0ds00 table 3-1 i/o states of the sio (si) and so pins reset cs sel c/d si (sio) so state three-wire/two-wire operating mode 0 i hi-z C reset state 11 i hi-z C chip nonselected state 1 0 1 1 i o* three-wire control mode 0 data write mode o data read mode 0 1 i hi-z two-wire control mode 0 data write mode o data read mode i : input state hi-z : high-impedance state o : output state : dont care o* : state in which 1 is output 3.2 data transfer format 3.2.1 three-wire data transfer (sel = 1) (1) control mode when the c/d input is set high, control mode is set to control data transfer. data transfer control involves the following processing. 1 register address setting 2 register read/write selection remark after reset (reset) cancellation, the state enabling writing to the register at address 0000b is set. caution in control mode, each data item is read every eighth clock pulse. (data of less than eight clock periods is ignored.) c/d sck sio a3 a2 a1 a0 r / w www.datasheet.in
m pD72042 24 data sheet s14870ej1v0ds00 (2) data read mode when the c/d pin is set low after register read is selected in control mode, the data read mode is set. in data read mode, the data in a read register is read on the so pin upon detecting the falling edge of the sck pin. caution when the c/d pin is set high in data read mode, the serial clock counter is reset. therefore, the remaining bits of the byte cannot be read; at the next falling edge, read is performed starting from the next byte in the case of rbf, or from the first bit for other registers. c/d sck si a3 a2 a1 a0 d7 d6 d5 d4 d3 d2 d1 d0 so state control mode (selection of register read) data read mode serial clock counter reset pointer 1 ? (3) data write mode when the c/d pin is set low after register write has been selected in control mode, data write mode is set. in data write mode, data for a write register is applied to the si pin at the rising edge of the sck pin. c/d sck si a3 a2 a1 a0 d7 d6 d5 d4 d3 d2 d1 d0 so 0 state control mode (selection of register write) data write mode serial clock counter reset pointer ? caution register overwrite is started immediately after the eighth clock rising edge. all registers other than tbf are overwritten on the eighth clock rising edge. (data of less than eight clock periods is ignored.) www.datasheet.in
m pD72042 25 data sheet s14870ej1v0ds00 3.2.2 two-wire data transfer (sel = 0) (1) control mode when the c/d input is set high, control mode is set to control data transfer. data transfer control involves the following processing. 1 register address setting 2 register read/write selection remark after reset (reset) cancellation, the state enabling writing to the register at address 0000b is set. caution in control mode, each data item is read every eighth clock pulse. (data of less than eight clock periods is ignored.) c/d sck sio a3 a2 a1 a0 r / w (2) data read mode note sio pin input state sio pin output state cautions 1. when the c/d pin is set high in data read mode, the serial clock counter is reset. therefore, the remaining bits of the byte cannot be read; at the next falling edge, a read operation is performed starting from the next byte in the case of rbf, or from the first bit for other registers. 2. the sio pin is a cmos i/o pin. so, be careful to avoid an output collision between the sio pin and the microcomputer. further, a pull-up resistor is required when n-ch open-drain output of the microcomputer is used. note that if the last output level is low upon the termination of read mode, current will flow constantly. c/d sck sio note a3 a2 a1 a0 d7 d6 d5 d4 d3 d2 d1 d0 1 serial clock counter reset pointer state control mode (selection of register read) data read mode www.datasheet.in
m pD72042 26 data sheet s14870ej1v0ds00 (3) data write mode note sio pin input state caution register overwrite is started immediately after the eighth clock rising edge. all registers other than tbf are overwritten at the eighth clock rising edge. (data of less than eight clock periods is ignored.) c/d sck sio note a3 a2 a1 a0 d7 d6 d5 d4 d3 d2 d1 d0 0 state control mode (selection of register write) date write mode serial clock counter reset pointer www.datasheet.in
m pD72042 27 data sheet s14870ej1v0ds00 3.3 connection to a microcomputer (1) three-wire serial i/o (2) two-wire serial i/o notes 1. when only the m pD72042 is to be controlled from a microcomputer via a serial i/o interface, the cs pin must be tied low (by connecting it to gnd). 2. when an interrupt is detected by polling (in flg register read), irq may be left open. when high-volume or high-speed data transfer is required, however, the system described above is recommended to ensure reliable data transfer. 3. required when the microcomputers n-ch open-drain output is used. the sio pin of the m pD72042 is a cmos i/o pin. 120 w 5 v v dd av dd test bus+ bus xi xo gnd sel cs note 1 c/d sck si so irq note 2 reset output port output port sck so si int low voltage detection circuit 75xl series 78k series 6 mhz 120 w 5 v pD72042 microcomputer m microcomputer 120 w 5 v 6 mhz 120 w 75xl series 78k series low voltage detection circuit v dd av dd test bus+ bus xi xo gnd sel cs note 1 c/d sck sio so irq note 2 reset output port output port sck sio int note 3 pD72042 5 v m www.datasheet.in
m pD72042 28 data sheet s14870ej1v0ds00 3.4 standby mode setting and cancellation standby mode can be set by setting streq of the ctr register to 1. the xi pin for oscillation is tied to gnd, and the impedance of the xo pin goes high. in standby mode (with the stm flag of the flg register set to 1), only the following registers can be accessed: writable register : ctr (address 0000b) readable register : flg (address 0001b) standby mode can be cancelled by setting streq of the ctr register to 0. caution do not read any data from internal registers via the serial i/o during the period from when a microcomputer sets the streq flag to 1 to when the m pD72042 enters the standby mode. this period is one-communication frame at maximum. 3.5 reset mode setting and cancellation for hardware reset, the registers are initialized and standby mode is set. (during this period, oscillation is stopped.) for software reset, the registers are initialized, and operation is started. www.datasheet.in
m pD72042 29 data sheet s14870ej1v0ds00 4. registers a microcomputer controls iebus communication by reading from and writing to the internal registers of the m pD72042. registers are classified into write registers and read registers. the total size of the write registers is 40 bytes; the transmission buffer uses 33 of the 40 bytes. the total size of the read registers is 49 bytes; the reception buffer uses 40 of the 49 bytes. table 4-1 lists the registers. www.datasheet.in
m pD72042 30 data sheet s14870ej1v0ds00 table 4-1 m pD72042 registers (a) write registers address name high-order 4 bits low-order 4 bits note reference page 0h 0000 ctr C C C reen srst C C streq a p. 31 1h 0001 cmr 0 lock bufc comc c p. 32 1 0 0 0 0 irs mfc derc 2h 0010 uar1 local station address condition code b p. 34 (low-order 4 bits) 3h 0011 uar2 local station address (high-order 8 bits) b p. 34 4h 0100 sar1 slave address 0 0 0 0 d p. 35 (low-order 4 bits) 5h 0101 sar2 slave address (high-order 8 bits) d p. 35 6h 0110 mcr broadcast bits number of control bits d p. 36 arbitrations 7h 0111 C C C C 8h 1000 C C C C eh 1110 tbf number of bytes of transmission data, transmission data f p. 38 address name high-order 4 bits low-order 4 bits note reference page 0h 0000 str tfl tep rfl rep C a p. 39 1h 0001 flg C marq strq slre cex raw stm irq a p. 40 2h 0010 rdr1 number of bytes of master reception data a p. 42 3h 0011 rdr2 number of bytes of slave reception data or a p. 42 broadcast reception data 4h 0100 lor1 lock address (low-order 8 bits) h p. 43 5h 0101 lor2 lock state lock address h p. 43 (high-order 4 bits) 6h 0110 dar1 broadcast address C e p. 44 (low-order 4 bits) 7h 0111 dar2 broadcast address (high-order 8 bits) e p. 44 8h 1000 rcr return codes (marc, slrc) a p. 45 eh 1110 rbf transmitter address, reception data g p. 57 (b) read registers note writable and readable periods of the registers of the m pD72042 a: arbitrary b: after system reset cancellation c: while cex of the flg register (address 0001) is set to 0 d: while marq of the flg register (address 0001) is set to 0 e: after slrc of the rcr register (address 1000) is set to 1100 (broadcast reception error) f: while tfl of the str register (address 0000) is set to 0 g: while rep of the str register (address 0000) is set to 0 h: when cex of the flg register (address 0001) is set to 0 after lock of the cmr register (address 0001) is set to 1 www.datasheet.in
m pD72042 31 data sheet s14870ej1v0ds00 cautions 1. in standby mode (with stm of the flg register set to 1), the user can only write to the ctr register (including standby mode cancellation) and read from the flg register. 2. never access a free address. 3. slave status (ssr) can be read into rbf by setting the control bits to 0h or 6h from the master unit. ctr address : 0000b (0h) read/write : write control register when reset : 00 1b ctr is a one-byte write register used to control m pD72042 operations. [reen] when reen is set to 1, the slre flag of the flg register is immediately set to 1 to enable both slave and broadcast reception. [srst] when srst is set to 1, the m pD72042 is immediately reset. (note, however, that streq is set to a written value.) [streq] 1: requests standby mode. 0: exits from standby mode. ? standby mode setting and cancellation the m pD72042 is requested to enter the standby mode by setting the streq flag to 1 from the microcomputer. the m pD72042 enters standby mode when the standby mode input enabled state (carrier sense state) is set. in this case, the impedance of the bus+ and busC pins goes high (logic 1), and the stm flag of the flg register is set to 1. in standby mode, oscillation is stopped, and all operations are stopped while preserving the internal data, thus minimizing power consumption. when, in standby mode, the streq flag is set to 0 from the microcomputer, standby mode is cancelled after the period (about 20 ms) needed for oscillation to stabilize; the halted operations are resumed from the point at which standby mode was set. at this time, the stm flag of the flg register changes to 0. in standby mode, only writing to the ctr register (for standby mode cancellation) and reading from the flg register can be performed from the microcomputer. cautions 1. when the srst flag and streq flag are simultaneously set to 1, standby mode is set after software reset. (this state is the same as that set by hardware reset.) note, however, that when the srst flag is set to 1 in standby mode, a software reset is performed, but this is not reflected in the flg register. 2. do not read any data from internal registers via the serial i/o during the period from when a microcomputer sets the streq flag to 1 to when the m pD72042 enters the standby mode. this period is one-communication frame at maximum. b7 b6 b5 b4 b3 b0 ctr b2 b1 reen srst streq www.datasheet.in
m pD72042 32 data sheet s14870ej1v0ds00 cmr address : 0001b (1h) read/write : write command register when reset : 00000000b cmr is a one-byte write register used to set a command for communication control, transmission/reception buffer control, or optional function setting. when data is set in cmr from the microcomputer, cex of the flg register is set to 1. when the m pD72042 processes the data set in cmr, cex is set to 0. after the microcomputer checks that cex of the flg register is set to 0, new data can be set in cmr. the following describes the data that is set in cmr. (1) when bit 7 (msb) of cmr is 0 [lock] : lock state setting command 1 : the value representing the lock state (0001 for locked or 0000 for not-locked) and lock address are output to lor1 and lor2. note, however, that when 0000 (not-locked) is output, any lock address value is ignored. 0 : the contents of lor1 and lor2 remain as is. [bufc] : transmission/reception buffer control command 00 : the transmission and reception buffers remain as is. 01 : the transmission buffer (tbf) is cleared. 10 : the reception buffer (rbf) is cleared. 11 : the data of the previous (latest) communication frame to be stored in the reception buffer (rbf) is cleared note 1 . [comc] : communication control command 0000: communication operation remains as is. 0001: the locked state is cancelled. 1000: master communication is requested note 2 . 1001: master communication is requested, with the previous master transmission state held note 3 . 1010: master communication is aborted. 1011: slave data transmission is requested note 4 . 1100: slave data transmission is requested, with the previous slave data transmission state held note 5 . 1101: slave data transmission is aborted. 1111: slave reception and broadcast reception are disabled. notes 1. if the microcomputer has already read the data for the previous (latest) communication frame from rbf, or optional function setting in cmr is selected and mfc = 0, clear rbf with bufc = 10. b7 0 b6 lock b5 bufc b4 b3 b0 comc cmr www.datasheet.in
m pD72042 33 data sheet s14870ej1v0ds00 notes 2. when the msb of the control bits set in mcr is 1 (for master transmission), set the number of bytes of transmission data, and at least one byte of transmission data in tbf before command setting. 3. when the msb of the control bits set in mcr is 1 (for master transmission), set at least one byte of transmission data before command setting. this operation is not required if all transmission data has already been set in tbf. 4. set the number of bytes of transmission data, and at least one byte of transmission data in tbf before command setting. 5. set at least one byte of transmission data in tbf before command setting. this operation is not required if all transmission data has already been set in tbf. (2) when bit 7 (msb) of cmr is 1 an optional function is set. [mfc] : selection of one frame/multiple frames 1 : data for multiple frames is stored in rbf. 0 : data for only one frame is stored in rbf. [derc] : broadcast reception selection 1 : the issue of return code 1100 (broadcast reception error) for slrc of the rcr register is enabled. 0 : the issue of return code 1100 (broadcast reception error) for slrc of the rcr register is disabled. [irs] : interrupt generation condition selection 0 : an interrupt is requested when the data of the rcr register changes. 1 : an interrupt is requested when the data of the rcr register changes to other than the following: marc = 0000b (start of master transmission) marc = 0100b (start of master reception) slrc = 0000b (start of slave data transmission) slrc = 0100b (start of slave reception) slrc = 1000b (start of broadcast reception) caution set an optional function in initialization processing after reset cancellation for the m pD72042. until an optional function has been set, the m pD72042 will not accept iebus communication. b7 1 b6 0 b5 0 b4 b3 b0 irs cmr b2 b1 0 0 mfc derc www.datasheet.in
m pD72042 34 data sheet s14870ej1v0ds00 uar1 address : 0010b (2h) (uar1) uar2 0011b (3h) (uar2) read/write : write local station unit address register when reset : undefined (with the previous data held) uar1 and uar2 are registers used to set a local station unit address (12 bits) and condition code. set uar1 and uar2 after reset cancellation. [local station address] a local station address is used as a master address when the local station performs communication as the master unit. a local station address is used as a slave address when the local station performs communication as a slave. [condition code] remark bit 1 of a condition code is not used. (set the bit to either 0 or 1.) b7 local station address (low-order 4 bits) b4 b3 b0 condition code uar1 b7 b0 local station address (high-order 8 bits) uar2 bit position condition code condition setting b3, b2 00 communication is performed in mode 0. 01 communication is performed in mode 1. 10 undefined 11 b0 0 the slave transmission section is disabled. 1 the slave transmission section is enabled. www.datasheet.in
m pD72042 35 data sheet s14870ej1v0ds00 sar1 address : 0100b (4h) (sar1) sar2 0101b (5h) (sar2) read/write : write slave address register when reset : undefined (the pre- vious data is held) the sar1 and sar2 registers are used to set the address of a remote station (slave address) in master communication. set sar1 and sar2 while the value of marq of the flg register is 0 (while master communication is not requested). b7 slave address (low-order 4 bits) b4 b3 b0 sar1 b7 b0 slave address (high-order 8 bits) sar2 0000 www.datasheet.in
m pD72042 36 data sheet s14870ej1v0ds00 mcr address : 0110b (6h) read/write : write master communication register when reset : undefined (the pre- vious data is held) the mcr register is used to set a master communication condition. set mcr while the value of marq of the flg register is 0 (while master communication is not requested). [broadcast bit] this bit is used to select broadcast or separate communication. bit 7 = 0: broadcast bit 7 = 1: separate communication [number of arbitrations] (number of retries) this field is used to set the maximum number of retry operations to be performed if arbitration is lost in master communication. the m pD72042 automatically retries communication as many times as the number set in this field. b7 broadcast bit b6 number of arbitrations b4 b3 b0 control bits mcr b6 b5 b4 number of retries 000 0 001 1 010 2 011 3 100 4 101 5 110 6 111 7 www.datasheet.in
m pD72042 37 data sheet s14870ej1v0ds00 [control bits] this control field is used to set the control bits (four bits). ? contents of control bits bit 3 note 1 bit 2 bit 1 bit 0 function note 2 0h 0 0 0 0 slave status (ssr) read 1h 0 0 0 1 undefined 2h 0 0 1 0 undefined 3h 0 0 1 1 data read and lock 4h 0 1 0 0 lock address read (low-order 8 bits) 5h 0 1 0 1 lock address read (high-order 4 bits) 6h 0 1 1 0 slave status (ssr) read and unlock 7h 0 1 1 1 data read 8h 1 0 0 0 undefined 9h 1 0 0 1 undefined ah 1 0 1 0 command write and lock bh 1 0 1 1 data write and lock ch 1 1 0 0 undefined dh 1 1 0 1 undefined eh 1 1 1 0 command write fh 1 1 1 1 data write notes 1. the value of bit 3 (msb) determines the transfer direction of the subsequent data-length field data and data field data. when bit 3 is set to 1: data is transferred from the master unit to a slave unit. when bit 3 is set to 0: data is transferred from a slave unit to the master unit. 2. 3h, 6h, ah, and bh are control bits used for lock setting and cancellation. when an undefined value of 1h, 2h, 8h, 9h, ch, or dh is sent, no acknowledgement is returned. www.datasheet.in
m pD72042 38 data sheet s14870ej1v0ds00 tbf address : 1110b (eh) read/write : write transmission buffer when reset : empty tbf is a 33-byte fifo buffer used to hold the number of bytes of transmission data and transmission data for master transmission and slave data transmission. tbf can be written from the microcomputer when the tfl flag of the str register is set to 0 (indicating that tbf is not full). in master transmission and slave data transmission, the following format is used to load data into tbf from the microcomputer. [byte 1] : number of bytes of transmission data between 1 and 256 bytes can be set. [bytes 2 and up] : transmission data as much transmission data as is set in byte 1 is set in byte 2 and subsequent bytes. byte 1 number of bytes of transmission data byte 2 first byte of transmission data byte 3 second byte of transmission data byte 33 tbf number of bytes of data set in byte 1 of tbf transmission data 1 01h 2 02h 255 ffh 256 00h www.datasheet.in
m pD72042 39 data sheet s14870ej1v0ds00 str address : 0000b (0h) read/write : read status register when reset : 0101 b str is a one-byte read register used to indicate the states of tbf and rbf. [tfl] 1 : tbf is full. 0 : tbf is not full. the microcomputer can load data into tbf. [tep] 1 : tbf is empty. the microcomputer can load initial data into tbf. 0 : tbf is not empty. [rfl] 1 : rbf is full. 0 : rbf is not full. [rep] 1 : rbf is empty. 0 : rbf is not empty. the microcomputer can read data from rbf. b7 tfl b6 tep b5 rfl b4 b3 b0 str b2 b1 rep www.datasheet.in
m pD72042 40 data sheet s14870ej1v0ds00 flg address : 0001b (1h) read/write : read flag register when reset : 00000010b flg is a one-byte read register used to indicate statuses such as the communication state, command execution state, and interrupt state. [marq] 1 : a request for communication as the master unit is being made. 0 : no request for communication as the master unit is being made. data can be written to the sar1, sar2, and mcr registers. the marq flag is set and reset as described below. ? set : when the cex flag of the flg register is set to 0 after 1000 or 1001 is set in comc of the cmr register ? reset : when master communication is terminated [strq] 1 : a request for slave unit data transmission is being made. 0 : no request for slave unit data transmission is being made. the strq flag is set and reset as described below. ? set : when the cex flag of the flg register is set to 0 after 1011 or 1100 is set in comc of the cmr register ? reset : when slave data transmission is terminated [slre] 1 : slave reception or broadcast is allowed. 0 : slave reception and broadcast are not allowed. the slre flag is set and reset as described below. ? set : when reen of the ctr register is set to 1 ? reset : when slave reception or broadcast reception is terminated normally or suspended, or when cex of the flg register is set to 0 after 1111 is set in comc of the cmr register when slre = 0, bit 1 of the slave status is set to 1 regardless of the state of rbf; communication frame reception based on the ah, bh, eh, and fh control bits, received from the master station, is not performed. b7 b6 marq b5 strq b4 b3 b0 raw flg b2 b1 slre cex stm irq www.datasheet.in
m pD72042 41 data sheet s14870ej1v0ds00 [cex] 1 : a command is currently being executed. 0 : execution of a command has terminated. a command code can be set in cmr. the cex flag is set and reset as described below. ? set : when a command code is set in cmr ? reset : when m pD72042 command processing is terminated [raw] 1 : the m pD72042 is running away. 0 : the m pD72042 is not running away. the raw flag is used to indicate a microprogram crash in the m pD72042, as detected by a watchdog timer. when the raw flag is set to 1, a request to interrupt the microcomputer is issued. an interrupt pulse signal is output on the irq pin, and the irq flag of the flg register is set. at this time. the microcomputer must reset the m pD72042 by driving the reset pin of the m pD72042 low or by setting the srst flag of the ctr register to 1. [stm] 1 : standby mode is set. 0 : standby mode is not set. [irq] 1 : an interrupt request was made. 0 : no interrupt request is made. the irq flag is set when a return code including the code in the rcr register is changed note , or when the raw flag changes from 0 to 1 (crash). when the flg register is read with the irq flag set to 1, the irq flag is reset. for details of the return codes, see the description of the rcr register. note irq flag setting depends on the irs value of the cmr register. www.datasheet.in
m pD72042 42 data sheet s14870ej1v0ds00 rdr1 address : 0010b (2h) (rdr1) rdr2 0011b (3h) (rdr2) read/write : read reception data register when reset : 00h the rdr1 and rdr2 registers are used to hold the number of bytes of reception data stored in rbf for each frame received during master, slave, or broadcast reception. [rdr1] rdr1 indicates the number of bytes of data set in rbf by a communication frame during master reception. one of the following values is set in rdr1: ? when master communication is requested (comc = 1000 or 1001) : rdr1 = 0 ? when master reception is started (marc = 0100) : rdr1 = 3 ? each time one byte of data is received : rdr1 is incremented by 1. [rdr2] rdr2 indicates the number of bytes of data set in rbf by a communication frame in slave reception or broadcast reception. one of the following values is set in rdr2: ? when slave reception is started (slrc = 0100) : rdr2 = 3 ? when broadcast reception is started (slrc = 1000) : rdr2 = 3 ? each time one byte of data is received : rdr2 is incremented by 1. ? example of rdr2 setting note n: number of bytes of data received with the previous communication frame b7 number of bytes of master reception data b0 rdr1 b7 b0 number of bytes of slave or broadcast reception data rdr2 f00101001100210 n note + 3 3 4 5 control bits p a data- length bits p a data p a data p a rdr2 communication frame www.datasheet.in
m pD72042 43 data sheet s14870ej1v0ds00 lor1 address : 0100b (4h) (lor1) lor2 0101b (5h) (lor2) read/write : read lock register when reset : 0 h (lor2) lor1 is undefined. the lor1 and lor2 registers are used to hold a lock state. lor1 and lor2 set a lock state and lock address after the lock state setting command is set in the cmr register (lock = 1), then executed. [lock state] 0000: not locked 0001: locked remark when 0000 (not locked) is set in the lock state bits, any lock address value is ignored. b7 lock state b4 b3 b0 lock address (high-order 4 bits) lor2 b7 b0 lock address (low-order 8 bits) lor1 www.datasheet.in
m pD72042 44 data sheet s14870ej1v0ds00 dar1 address : 0110b (6h) (dar1) high-order 4 bits dar2 0111b (7h) (dar2) read/write : read broadcast address register when reset : undefined the dar1 and dar2 registers are used to hold a broadcast address (master address) involved when a broadcast reception error occurs. dar1 and dar2 are updated each time a broadcast reception error occurs (slrc of the rcr register is set to 1100). so, ensure that when a broadcast reception error occurs, the contents of dar1 and dar2 are read by the microcomputer within the time indicated below. ? maximum allowable dar1 and dar2 read time: approx. 5420 m s (mode 0) approx. 1490 m s (mode 1) cautions 1. if the microcomputer cannot read the data in dar1 and dar2 within the times indicated above, dar1 and dar2 may be updated by the occurrence of another broadcast reception error, and the subsequently updated broadcast address may be read. 2. a broadcast address is stored in dar1 and dar2 when derc (broadcast reception selection) of the cmr register is set to 1. b7 broadcast address (low-order 4 bits) b4 b3 b0 dar1 b7 b0 broadcast address (high-order 8 bits) dar2 t irq www.datasheet.in
m pD72042 45 data sheet s14870ej1v0ds00 rcr address : 1000b (8h) read/write : read return code register when reset : 11111111b rcr is a one-byte read register used to indicate the iebus communication status (return code). rcr consists of two return codes: marc and slrc. marc indicates the communication status in master transmission or master reception. slrc indicates the communication status in slave data transmission, slave reception, or broadcast reception. when the contents of rcr change, an interrupt request is sent to the microcomputer according to the setting of the irs flag of the cmr register. the marc and slrc flags are set independently, such that the microcomputer can simultaneously read the master communication status and slave communication status. caution when irq is set as a result of a program crash, the previous value of rcr is preserved. [marc] marc represents a return code issued during master transmission or master reception. (a) master transmission master transmission is performed when the microcomputer performs the setting explained below. ? master transmission setting 1 in the low-order 4 bits of the mcr register, control bits (1010, 1011, 1110, or 1111) are set for master- to-slave data transfer. 2 in comc of the cmr register, a command (1000 or 1001) for requesting master communication is set. table 4-2 lists the marc return codes for master transmission. b7 marc b4 b3 b0 slrc rcr www.datasheet.in
m pD72042 46 data sheet s14870ej1v0ds00 table 4-2 marc return codes for master transmission marc description 0000 1. meaning : master transmission is started. 2. occurrence condition : this return code is issued when the master address field in a communication frame has been transmitted, and the unit has won the arbitration to become the master unit. 0001 1. meaning : master transmission data is not available. 2. occurrence condition : this return code is issued if the next transmission data is not set in tbf during master transmission. 3. microcomputer processing : if data consisting of one or more bytes is not set in tbf within the time below, transmission may be terminated prior to its completion. ? transmission data setting time: approx. 1570 m s (mode 0) approx. 390 m s (mode 1) 0010 1. meaning : master transmission was terminated normally. 2. occurrence condition : this return code is issued when as much data as the amount specified in the data-length field has been transmitted normally. in this case, the marq flag of the flg register changes from 1 to 0. 0011 1. meaning : master transmission was aborted. 2. occurrence condition : this return code is issued in any of the following cases. in each case, the marq flag of the flg register changes from 1 to 0. ? when the unit has lost the arbitration to become the master unit. ? when a transmission is stopped because the nak is returned from the slave unit at the end of the slave address field, the control field, or the data-length field of a communication frame (excluding the broadcast). ? when a communication is terminated prior to the transmission of as much data as the amount specified in the data-length field of a communication frame. (b) master reception master reception is performed when the microcomputer performs the setting below. ? master reception setting 1 in the low-order 4 bits of the mcr register, control bits (0000, 0011, 0100, 0101, 0110, or 0111) are set for slave-to-master data transfer. 2 in comc of the cmr register, a command (1000 or 1001) for requesting master communication is set. table 4-3 indicates the marc return codes for master reception. www.datasheet.in
m pD72042 47 data sheet s14870ej1v0ds00 table 4-3 marc return codes for master communication marc description 0100 1. meaning : master reception has started. 2. occurrence condition : 1 the unit has won the arbitration to become the master unit, and a communication frame up to the data-length field was transferred successfully. 2 when the control field is received, rbf becomes ready for reception note . after the data-length field, 0000 is set in marc, and three-byte data consisting of a slave address, control bits, and data-length bits is set in rbf. if rbf becomes full when this three-byte data is set, 0001 is set in marc. 3. microcomputer processing : three-byte data consisting of a slave address, control bits, and data- length bits can be read from rbf. 0101 1. meaning : the master reception buffer is full. 2. occurrence condition : this return code is issued when rbf becomes full during data reception as the master unit, and reception data cannot be set in rbf. 3. microcomputer processing : if data consisting of one or more bytes is not read from rbf within the time below, the one-byte data cannot be received, and the m pD72042 returns an nak. ? reception data read time: approx. 1570 m s (mode 0) approx. 390 m s (mode 1) 0110 1. meaning : master reception was terminated normally. 2. occurrence condition : this return code is issued when as much data as the amount specified in the data-length field has been received normally in a communication frame. in this case, the marq flag of the flg register changes from 1 to 0. 3. microcomputer processing : reception data can be read from rbf, and the number of bytes of master reception data can be read from rdr1. 0111 1. meaning : master reception was aborted. 2. occurrence condition : this return code is issued in any of the following cases. in each case, the marq flag of the flg register changes from 1 to 0. ? when the unit has lost the arbitration to become the master unit. ? when a transmission is stopped because the nak is returned from the slave unit at the end of the slave address field or the control field of a communication frame or because the nak is sent to the slave unit at the end of the data-length field of a communication frame (excluding the broadcast). ? when a communication is terminated prior to the reception of as much data as the amount specified in the data-length field of a communication frame. 3. microcomputer processing : reception data can be read from rbf, and the number of bytes of master reception data can be read from rdr1. note see note of table 4-9. www.datasheet.in
m pD72042 48 data sheet s14870ej1v0ds00 [marc occurrence interval] (a) when master transmission is performed table 4-4 minimum return code occurrence interval for master transmission interval mode 0 mode 1 ta approx. 2430 m s approx. 740 m s tb approx. 90 m s approx. 90 m s tc approx. 4710 m s approx. 1170 m s td approx. 6290 m s approx. 1570 m s te approx. 20 m s approx. 20 m s tf approx. 1570 m s approx. 390 m s tg approx. 7150 m s approx. 1920 m s 0010 0011 0110 0111 ta tb 0000 0011 0011 0010 0001 tc td te tf tf te ta tb tg 0001 0010 0011 0000 0011 0111 0100 return codes for master transmission and master reception return codes for master transmission and master reception return codes for master transmission t irq www.datasheet.in
m pD72042 49 data sheet s14870ej1v0ds00 (b) when master reception is performed table 4-5 minimum return code occurrence interval for master reception interval mode 0 mode 1 ta approx. 7150 m s approx. 1920 m s tb approx. 90 m s approx. 90 m s tc approx. 1570 m s approx. 390 m s td approx. 20 m s approx. 20 m s te approx. 2430 m s approx. 740 m s t irq 0010 0011 0110 0111 ta tb 0100 0111 0111 0110 0101 tc tc td tc tc td te tb ta 0001 0110 0111 0000 0011 0111 0100 ta return codes for master transmission and master reception return codes for master reception return codes for master transmission and master reception www.datasheet.in
m pD72042 50 data sheet s14870ej1v0ds00 [slrc] slrc indicates the communication status for slave data transmission, slave reception, or broadcast reception. (a) slave data transmission slave data transmission is performed when the microcomputer makes the setting described below. ? slave data transmission setting in comc of the cmr register, a command (1011 or 1100) for requesting slave data transmission is set from the microcomputer. table 4-6 slrc return codes in slave data transmission slrc description 0000 1. meaning : slave data transmission has been started. 2. occurrence condition : this return code is issued when the control bits (0011 or 0111) requesting data transmission are received from the master unit. 0001 1. meaning : slave transmission data is not available. 2. occurrence condition : this return code is issued when the next transmission data is not set in tbf during slave data transmission. 3. microcomputer processing : if data consisting of one or more bytes is not set in tbf within the time below, transmission may be terminated prior to its completion. ? transmission data setting time : approx. 1570 m s (mode 0) approx. 390 m s (mode 1) 0010 1. meaning : slave data transmission was terminated normally. 2. occurrence condition : this return code is issued when as much data as the amount specified in the data-length field has been transmitted normally. in this case, the strq flag of the flg register changes from 1 to 0. 0011 1. meaning : slave data transmission was aborted. 2. occurrence condition : this return code is issued when communication is terminated prior to the transmission of as much data as the amount specified in the data-length field in a communication frame. in this case, the strq flag of the flg register changes from 1 to 0. www.datasheet.in
m pD72042 51 data sheet s14870ej1v0ds00 (b) slave reception slave reception is performed when the broadcast bit is set to 1, and a communication frame with the local station address specified in the slave address field is received. table 4-7 indicates the slrc return codes for slave reception. table 4-7 slrc return codes for slave reception slrc description 0100 1. meaning : slave reception is started. 2. occurrence condition : 1 a separate communication frame up to the data-length field was received normally from the master unit. 2 once the control field has been received, rbf is ready for reception note . after the data-length field, 0100 is set in slrc, and three-byte data consisting of a master address, control bits, and data-length bits is set in rbf. 3. microcomputer processing : three-byte data consisting of a master address, control bits, and data- length bits can be read from rbf. 0101 1. meaning : the slave reception buffer is full. 2. occurrence condition : this return code is issued when rbf becomes full during data reception as a slave unit, and reception data cannot be set in rbf. 3. microcomputer processing : if data consisting of one or more bytes is not read from rbf within the period indicated below, the one-byte data cannot be received, and the m pD72042 returns an nak. ? reception data read time: approx. 1570 m s (mode 0) approx. 390 m s (mode 1) 0110 1. meaning : slave reception was terminated normally. 2. occurrence condition : this return code is issued when as much data as the amount specified in the data-length field has been received normally in a communication frame. in this case, the slre flag of the flg register changes from 1 to 0. 3. microcomputer processing : reception data can be read from rbf, and the number of bytes of slave reception data can be read from rdr2. 0111 1. meaning : slave reception was aborted. 2. occurrence condition : this return code is issued when reception is terminated prior to the reception of as much data as the amount specified in the data-length field of a communication frame. in this case, the slre flag of the flg register changes from 1 to 0. 3. microcomputer processing : reception data can be read from rbf, and the number of bytes of slave reception data can be read from rdr2. note see note of table 4-9. www.datasheet.in
m pD72042 52 data sheet s14870ej1v0ds00 (c) broadcast reception broadcast reception is performed when the broadcast bit is set to 0, and a communication frame with ffh (general broadcast) or the local station group address specified in the slave address field is received. table 4-8 indicates the slrc return codes for broadcast reception. table 4-8 slrc return codes for broadcast reception slrc description 1000 1. meaning : broadcast reception is started. 2. occurrence condition : 1 a broadcast frame up to the data-length field was received from the master unit normally. 2 once the control field has been received, rbf is ready for reception note . after the data-length field, 1000 is set in slrc, and three-byte data consisting of a master address, control bits, and data-length bits is set in rbf. 3. microcomputer processing : three-byte data consisting of a master address, control bits, and data- length bits can be read from rbf. 1001 1. meaning : the broadcast reception buffer is full. 2. occurrence condition : this return code is issued when rbf becomes full during data reception as a slave unit, preventing subsequent reception data from being set in rbf. 3. microcomputer processing : if data consisting of one or more bytes is not read from rbf within the time below, broadcast reception is aborted. ? reception data read time: approx. 1570 m s (mode 0) approx. 390 m s (mode 1) 1010 1. meaning : broadcast reception was terminated normally. 2. occurrence condition : this return code is issued when as much data as the amount specified in the data-length field has been received normally in a communication frame. in this case, the slre flag of the flg register changes from 1 to 0. 3. microcomputer processing : reception data can be read from rbf, and the number of bytes of broadcast reception data can be read from rdr2. 1011 1. meaning : broadcast reception was aborted. 2. occurrence condition : this return code is issued when reception is terminated prior to the reception of as much data as the amount specified in the data-length field in a communication frame. in this case, the slre flag of the flg register changes from 1 to 0. 3. microcomputer processing : reception data can be read from rbf, and the number of bytes of broadcast reception data can be read from rdr2. note see note of table 4-9. www.datasheet.in
m pD72042 53 data sheet s14870ej1v0ds00 table 4-9 indicates the slrc return code issued in broadcast reception when an optional function is set in the cmr register with derc = 1. table 4-9 slrc return code in broadcast reception when the optional function is set (derc = 1) slrc description 1100 1. meaning : broadcast reception error 2. occurrence condition : this return code is issued if rbf is not ready for reception note when the control field is received. in this case, the master address in the communication frame is set as a broadcast address in dar2 and dar1. 3. microcomputer processing : a broadcast address can be read from dar1 and dar2. however, the data of dar1 and dar2 is updated each time a broadcast reception error occurs. so, ensure that data is read from dar1 and dar2 within the interval indicated below. ? read time: approx. 5420 m s (mode 0) approx. 1490 m s (mode 1) note rbf is ready for reception according to the optional function setting in cmr, as described below. (i) when mfc = 0 the slre flag of the flg register is 1 (slave reception and broadcast reception only); and rbf is empty. (ii) when mfc = 1 the slre flag of the flg register is 1 (slave reception and broadcast reception only); and rbf has at least 4 bytes of free space. when rbf is ready for reception, bit 1 of slave status transmitted from the master unit with control bits 0000 or 0110 is set to 0. www.datasheet.in
m pD72042 54 data sheet s14870ej1v0ds00 [slrc occurrence interval] (a) when slave data transmission is performed table 4-10 minimum return code occurrence interval for slave data transmission interval mode 0 mode 1 ta approx. 5420 m s approx. 1490 m s tb approx. 1570 m s approx. 390 m s tc approx. 3140 m s approx. 780 m s td approx. 20 m s approx. 20 m s te approx. 7150 m s approx. 1920 m s 0010 0011 0110 0111 1010 1011 1100 ta 0000 0011 0010 0001 tb tc td tb tb td ta te ta 0001 0010 0011 0000 0100 1000 1100 return codes for broadcast reception, slave data transmission, and slave reception return codes for slave data transmission return codes for broadcast reception, slave data transmission, and slave reception t irq www.datasheet.in
m pD72042 55 data sheet s14870ej1v0ds00 (b) when slave reception is performed table 4-11 minimum return code occurrence interval for slave reception interval mode 0 mode 1 ta approx. 7150 m s approx. 1920 m s tb approx. 1570 m s approx. 390 m s tc approx. 20 m s approx. 20 m s td approx. 5420 m s approx. 1490 m s 0010 0011 0110 0111 1010 1011 1100 ta 0100 0111 0110 0101 tb tb tc tb tb tc td ta td 0101 0110 0111 0000 0100 1000 1100 return codes for broadcast reception, slave data transmission, and slave reception return codes for slave reception return codes for broadcast reception, slave data transmission, and slave reception t irq www.datasheet.in
m pD72042 56 data sheet s14870ej1v0ds00 (c) when broadcast reception is performed table 4-12 minimum return code occurrence interval for broadcast reception interval mode 0 mode 1 ta approx. 7150 m s approx. 1920 m s tb approx. 5420 m s approx. 1490 m s tc approx. 1570 m s approx. 390 m s td approx. 20 m s approx. 20 m s 0010 0011 0110 0111 1010 1011 1100 ta 1000 1011 1010 1001 tc tc td tc tc td tb ta tb 1001 1010 1011 0000 0100 1000 1100 tb 1100 return codes for broadcast reception, slave data transmission, and slave reception return codes for broadcast reception return codes for broadcast reception, slave data transmission, and slave reception t irq www.datasheet.in
m pD72042 57 data sheet s14870ej1v0ds00 rbf address : 1110b (eh) read/write : read reception buffer when reset : undefined rbf is a 40-byte fifo buffer used to hold a transmitter address, control bits, data-length bits, and reception data for master reception, slave reception, or broadcast reception. rbf can be read by the microcomputer when the rep flag of the str register is 0 (indicating that rbf is not empty). when an optional function is set in the cmr register with mfc = 1, multiple communication frames can be held in rbf until rbf becomes full. in master reception, slave reception, and broadcast reception, the format below is used to transfer data from rbf to the microcomputer. rbf high-order 4 bits low-order 4 bits byte 2 byte 1 byte 3 byte 4 byte 5 byte 40 transmitter address (high-order 8 bits) transmitter address (low-order 4 bits) control bits data-length bits first byte of reception data second byte of reception data last reception data transmitter address (high-order 8 bits) transmitter address (low-order 4 bits) control bits data-length bits first byte of reception data second byte of reception data last reception data communication frame 1 communication frame 2 www.datasheet.in
m pD72042 58 data sheet s14870ej1v0ds00 [byte 1, byte 2 (high-order 4 bits)] : transmitter address as indicated below, the transmitter address depends on whether the communication mode is master reception, slave reception, or broadcast reception. ? transmitter address case transmitter address master reception slave address slave reception master address broadcast reception [byte 2 (low-order 4 bits)] : control bits [byte 3] : data-length bits [byte 4 and up] : reception data the number of bytes of reception data is set in the rdr1 or rdr2 register, as described below. rdr1: number of bytes of reception data in master reception rdr2: number of bytes of reception data in slave reception or broadcast reception the number of bytes of reception data indicates the number of bytes of data received normally within a communication frame. this means that the number of bytes of reception data will match the length set in the data- length field of a communication frame only when the data has been received normally. www.datasheet.in
m pD72042 59 data sheet s14870ej1v0ds00 5. example timings for communication this chapter provides examples of the timings at which the contents of internal registers change during communication. the following seven examples are given: (1) master transmission timing example 1 timing at which a return code is generated upon the start of master transmission and at the normal termination of transmission (2) master transmission timing example 2 timing at which a return code is generated upon the start of master transmission, transmission data empty, and the suspension of transmission (3) slave data transmission timing example timing at which a return code is generated upon the start of slave data transmission and the normal termination of transmission (4) master reception timing example timing at which a return code is generated upon the start of master reception and the normal termination of reception (5) slave reception timing example 1 timing at which a return code is generated upon the start of slave reception and the normal termination of reception (6) slave reception timing example 2 timing at which a return code is generated upon the start of slave reception, reception buffer full, and the normal termination of reception (7) broadcast reception timing example timing at which a return code is generated upon the occurrence of an error during broadcast reception www.datasheet.in
m pD72042 60 data sheet s14870ej1v0ds00 (1) master transmission timing example 1 cmr flg comc cex marq strq slre marc slrc "0" 1000 0100 irq pin minimum time approx. 2430 s (mode 0) approx. 740 s (mode 1) communication frame control field data-length field data field header master address field control field data field 0000 (master transmission started) 0010 (master transmission terminated normally) 0110 (slave reception terminated) (slave reception started) rcr slave address field data-length field m m www.datasheet.in
m pD72042 61 data sheet s14870ej1v0ds00 (2) master transmission timing example 2 cmr flg comc cex marq strq slre marc slrc "0" irq pin "0" "1" tep rcr str tbf communication frame minimum time master address bits slave address bits control bits data-length bits ppapapapa papa data 1 data 31 data 32 0000 (master transmission started) (master transmission suspended) 0011 0001 (master transmission data empty) approx. 1570 s (mode 0) approx. 390 s (mode 1) m m www.datasheet.in
m pD72042 62 data sheet s14870ej1v0ds00 (3) slave data transmission timing example cmr flg comc cex marq strq slre marc slrc "0" 1011 0100 irq pin rcr minimum time approx. 5420 s (mode 0) approx. 1490 s (mode 1) communication frame control field data-length field data field header slave address field data field (slave reception started) 0110 (slave reception terminated) 0000 (slave data transmission started) 0010 (slave data transmission terminated normally) m m master address field control field data-length field www.datasheet.in
m pD72042 63 data sheet s14870ej1v0ds00 (4) master reception timing example note data-length bit: n cmr flg comc cex marq strq slre marc slrc "0" irq pin rcr rdr1 communication frame minimum time approx. 7150 s (mode 0) approx. 1920 s (mode 1) control field data-length field data field header master address field data field (master reception started) 0100 0110 (master reception terminated normally) (slave reception started) 0100 0110 (slave reception terminated) 3 4 n + 3 n + 2 1000 m m slave address field control field data- length field note www.datasheet.in
m pD72042 64 data sheet s14870ej1v0ds00 (5) slave reception timing example 1 ctr flg reen cex marq strq slre marc slrc irq pin rcr rdr2 communication frame "0" "0" "0" minimum time approx. 5260 s (mode 0) approx. 1450 s (mode 1) control field data-length field data field header master address field data field separate frame (data-length bits: n1) broadcast frame (data-length bits: n2) 1000 (broadcast reception started) 3 4 n1 + 3 n1 + 2 1010 (broadcast reception terminated normally) (slave reception started) 0100 0110 (slave reception terminated normally) 3 4 n2 + 3 n2 + 2 slave address field control field data-length field m m www.datasheet.in
m pD72042 65 data sheet s14870ej1v0ds00 (6) slave reception timing example 2 cmr flg lock cex marq strq slre marc slrc "0" irq pin rfl rcr str lor1, lor2 communication frame rbf "0" minimum time data-length bits: 24 pa 0 data 1 pa 0 data 22 pa 0 data 23 pa 1 pa 0 data 23 pa 0 data 24 (last) 0100 (slave reception started) 0101 (slave reception buffer full) 0110 (slave reception terminated normally) ack ack ack nak ack ack lock address approx. 1570 s (mode 0) approx. 390 s (mode 1) m m www.datasheet.in
m pD72042 66 data sheet s14870ej1v0ds00 (7) broadcast reception timing example ctr flg reen cex marq strq slre marc slrc "0" irq pin rfl rcr str dar1, dar2 communication frame "0" "0" "0" minimum time approx. 5420 s (mode 0) approx. 1490 s (mode 1) control field data-length field data field header master address field control field broadcast frame separate frame 0100 (slave reception started) 0110 (slave reception terminated normally) 1100 (broadcast reception error) master address slave address field m m www.datasheet.in
m pD72042 67 data sheet s14870ej1v0ds00 6. example microcomputer processing flow this chapter provides an example of the processing flow for controlling the m pD72042 from the microcomputer. the main parts of this example processing flow are the following two routines: ? main routine performs processing based on the communication flags set by the interrupt routine. ? interrupt routine sets the communication flags by reading the statuses of the m pD72042 upon the issue of an interrupt request. www.datasheet.in
m pD72042 68 data sheet s14870ej1v0ds00 name description rawf program crash detection flag (1: detected, 0: not detected) trrq transmission processing request flag (1: requested, 0: not requested) trcf transmission status (trc stored) i number of bytes in transmission data set in tbf rerq note reception processing request flag (1: requested, 0: not requested) recf note reception status (rec stored) size note number of bytes in reception data which can be read from rbf (rdr1/rdr2 stored) pw note write pointer for rerq, recf, and size pr note read pointer for rerq, recf, and size j number of bytes in reception data which has actually been read from rbf mcrq master communication processing request flag (1: requested, 0: not requested) sdrq slave data transmission processing request flag (1: requested, 0: not requested) corq command processing request flag (1: requested, 0: not requested) mtrqf master transmission request flag (1: requested, 0: not requested) mrrqf master reception request flag (1: requested, 0: not requested) strqf slave data transmission request flag (1: requested, 0: not requested) slref slave broadcast reception enable flag (1: enabled, 0: disabled) pointer rerq recf size 0 1 ............ 6.1 communication flags table 6-1 lists the communication flags used in the main and interrupt routines, excluding those flags assigned to the registers of the m pD72042. table 6-1 communication flags note rerq, recf, and size are stored in a buffer pair pointed to by pw and pr. ? buffer configuration remark buffers pointed to by the write pointer (pw) : rerq w , recf w , and size w buffers pointed to by the read pointer (pr) : rerq r , recf r , and size r www.datasheet.in
m pD72042 69 data sheet s14870ej1v0ds00 6.2 main routine fig. 6-1 shows the processing flow of the main routine. fig. 6-1 processing flow of main routine note communication flags mcrq, sdrq, and corq are set to 1 by the application processing routine. start ; see section 6.4.1 . initial setting routine communication flag initialization routine ; see section 6.4.2 . ; initialize if program crash is detected. transmission processing routine reception processing routine master communi- cation processing routine slave data trans- mission processing routine command processing routine ; see section 6.4.6 . ; see section 6.4.7 . ; see section 6.4.4 . ; see section 6.4.5 . ; see section 6.4.3 . application processing routine rawf? trrq? 0 0 rerq? 0 mcrq note ? 0 sdrq note ? 0 corq note ? 0 1 1 1 1 1 1 trrq 0 rerq 0 mcrq 0 sdrq 0 corq 0 m pD72042 www.datasheet.in
m pD72042 70 data sheet s14870ej1v0ds00 6.3 interrupt routine the interrupt routine performs the required processing when an interrupt request is issued from the m pD72042. the interrupt routine disables the interrupts received from the m pD72042, reads the statuses (flg and rcr registers) of the m pD72042, and sets the communication flags to be used by the main routine. to enable the handling of an interrupt request which may occur while the interrupts from the m pD72042 are disabled, do not clear the interrupt flags such that such a request can be detected upon the completion of the interrupt routine processing (see fig. 6-2 ). fig. 6-2 operation when an interrupt occurs during execution of interrupt routine irq rcr microcompute routine main routine (interrupts enabled) interrupt routine (interrupts disabled) interrupt routine (interrupts disabled) www.datasheet.in
m pD72042 71 data sheet s14870ej1v0ds00 fig. 6-3 flow of interrupt routine notes 1. the return code in marc is enabled when any of conditions, 1 , 2 , or 3 , below, is satisfied: 1 marc has been changed note 3 . 2 mtrqf = 1 and marq = 0 3 mrrqf = 1 and marq = 0 2. the return code in slrc is enabled when any of conditions, 1 , 2 , or 3 , below, is satisfied: 1 slrc has been changed note 3 . 2 strqf = 1 and strq = 0 3 slref = 1 and slre = 0 3. when marc is 0001 or 0101, the same value may be generated consecutively, such that marc is set to 1111 to enable the detection of a change in marc the next time it is generated. when slrc is 0001, 0101, or 1001, it is again set to 1111 for the same reason. start disable interrupts from read flg raw? 1 0 ; program crash? read rcr ; see note 1 . is return code in marc enabled? marc? 011 00 010 ; classify marc. rerq w ? 1 size w ? rdr1 recf w ? marc is return code in slrc enabled? n rerq w ? 1 size w ? rdr2 recf w ? slrc slrc? y 010 , 100 011 , 101 00 trcf ? slrc trrq ? 1 enable interrupts from end reti ; initialize rerq. ; initialize size. ; classify slrc. ; see note 2 . ; initialize rerq. ; initialize size. rawf ? 1 trcf ? marc trrq ? 1 increment pw rerq w ? 0 size w ? 0 rerq w ? 1 size w ? rdr1 recf w ? marc rerq w ? 1 size w ? rdr2 recf w ? slrc reen ? 1 increment pw rerq w ? 0 size w ? 0 m pD72042 n y m pD72042 www.datasheet.in
m pD72042 72 data sheet s14870ej1v0ds00 6.4 processing routines this section describes the processing routines called from the main routine. 6.4.1 m pD72042 initial setting routine this routine is executed when the m pD72042 is first started or upon the detection of a program crash (raw = 1). fig. 6-4 shows the flow of the m pD72042 initial setting routine. fig. 6-4 m pD72042 initial setting routine note there are two methods of performing reset, as follows: 1 set the reset pin to low. 2 set srst in ctr to 1. type 1 reset causes the m pD72042 to enter standby mode, thus requiring the subsequent release of standby mode. caution to enable normal iebus communication, always perform the above initial setting. 6.4.2 communication flag initialization routine this routine initializes the communication flags listed in table 6-1, as follows: rawf ? 0 trrq w ? 0 rerq w ? 0 size w ? 0 j ? 1 pw ? 0 pr ? 0 mcrq ? 0 sdrq ? 0 corq ? 0 mtrqf ? 0 mrrqf ? 0 strqf ? 0 slref ? 0 start reset pD72042 note uar1 ? local station address (four low-order bits) uar2 ? local station address (eight high-order bits) end cmr ? 100000 b1 b0 ; set local address and condition code. ; set condition code. ; set optional functions. condition code m www.datasheet.in
m pD72042 73 data sheet s14870ej1v0ds00 6.4.3 command processing routine this routine is executed when corq has been set by the application processing routine. the command processing routine sets a command code, in the cmr register, to set the lock state, control transmission/reception buffers, control communication, and set optional functions. the commands for master communication and slave data transmission request are described in sections 6.4.4 and 6.4.5 . fig. 6-5 shows the flow of the command processing routine. fig. 6-5 command processing routine 6.4.4 master communication processing routine this routine is executed when mcrq has been set by the application processing routine. the master communication processing routine consists of the following three processing routines: ? master transmission processing routine 1 this routine is used to transmit data, as the master unit, starting from the first data in tbf. ? master transmission processing routine 2 this routine is used to start master transmission from the point at which the previous master transmission was suspended. ? master reception processing routine this routine is used to receive data, as the master unit, from a slave unit. start read flg cmr ? command code end ; cex? 0 1 waiting for termination of previous command? www.datasheet.in
m pD72042 74 data sheet s14870ej1v0ds00 (1) master transmission processing routine 1 fig. 6-6 shows the flow of master transmission processing routine 1. fig. 6-6 flow of master transmission processing routine 1 start sar1 ? slave address (four low-order bits) sar2 ? slave address (eight high-order bits) mcr ? broadcast bits, number of arbitrations, and control bits (the msb is 1.) read str tep? 1 0 read flg cex? 0 1 cmr ? 00010000 read flg cex? 0 1 tbf ? number of bytes in transmission data | ? 1 i > n y read str tfl? 1 0 | ? | + 1 tbf ? transmission data (i-th byte) 1 read flg cex? 0 end cmr ? 00001000 mtrqf ? 1 ; waiting for termination of previous command? ; set clear command for transmission buffer. ; waiting for termination of processing of transmission buffer clear command? ; initialize |. ; setting tranmission data in tbf completed? ; ; waiting for termination of processing of master communication request command? number of bytes in tranmission data set master communication request command. www.datasheet.in
m pD72042 75 data sheet s14870ej1v0ds00 (2) master transmission processing routine 2 fig. 6-7 shows the flow of master transmission processing routine 2. fig. 6-7 flow of master transmission processing routine 2 start i > y n read str tfl? 1 0 tbf ? transmission data (i-th byte) | ? | + 1 read flg cex? cmr ? 00001001 read flg cex? 0 mtrqf ? 1 end 1 1 ; waiting for terminaton of previous command? ; set master communication continuation command. ; ; waiting for termination of processing of master communication continuation command? number of bytes in tranmission data 0 setting tranmission data in tbf completed? www.datasheet.in
m pD72042 76 data sheet s14870ej1v0ds00 (3) master reception processing routine fig. 6-8 shows the flow of the master reception processing routine. fig. 6-8 flow of master reception processing routine start sar1 ? slave address (four low-order bits) sar2 ? slave address (eight high-order bits) mcr ? broadcast bits, number of arbitrations, and control bits (the msb is 0.) read flg cex? 1 0 cmr ? 00001000 read flg cex? end mrrqf ? 1 ; ; set master communication request command. ; waiting for termination of previous command? ; 1 0 set data only when changing sar1, sar2, or mcr. waiting for termination of processing of master communication request command? www.datasheet.in
m pD72042 77 data sheet s14870ej1v0ds00 6.4.5 slave data transmission processing routine this routine is executed when sdrq has been set by the application processing routine. the slave data transmission processing routine consists of the following two processing routines: ? slave data transmission processing routine 1 this routine is used to transmit data, starting from the first data in tbf, when requested from the master unit. ? slave data transmission processing routine 2 this routine is used to start slave data transmission from the point at which the previous slave data transmission was suspended. (1) slave data transmission processing routine 1 fig. 6-9 shows the flow of slave data transmission processing routine 1. www.datasheet.in
m pD72042 78 data sheet s14870ej1v0ds00 fig. 6-9 flow of slave data transmission processing routine 1 1 0 0 1 y n 0 1 0 1 0 1 start read str tep? read flg cex? cmr ? 00010000 cex? read flg tbf ? number of bytes in transmission data | ? 1 read str i > number of bytes in tranmission data tfl? | ? | + 1 tbf ? transmission data (i-th byte) cmr ? 00001011 read flg end cex? strqf ? 1 ; set slave data transmission request command. ; setting of tranmission data in tbf completed? ; initialize i. ; waiting for termination of processing of transmission buffer clear command? ; set clear command for transmission buffer. ; waiting for termination of previous command? www.datasheet.in
m pD72042 79 data sheet s14870ej1v0ds00 (2) slave data transmission processing routine 2 fig. 6-10 shows the flow of slave data transmission processing routine 2. fig. 6-10 flow of slave data transmission processing routine 2 cmr ? 00001100 y n 0 1 0 1 0 1 start i > number of bytes in tranmission data read str tfl? | ? | + 1 tbf ? transmission data (i-th byte) cex? read flg cex? read flg strqf ? 1 end ; ; set slave data transmission continuation command. ; waiting for termination of previous command? ; 0 waiting for termination of processing of slave data transmission continuation command? setting of tranmission data in tbf completed? www.datasheet.in
m pD72042 80 data sheet s14870ej1v0ds00 6.4.6 transmission processing routine this routine is executed when trrq has been set by the interrupt routine during the execution of master transmission processing routine 1 (see 6.4.4 (1) ), master transmission processing routine 2 (see 6.4.4 (2) ), or the slave data transmission processing routine (see 6.4.5 ). fig. 6-11 shows the flow of the transmission processing routine. fig. 6-11 flow of transmission processing routine notes 1. indicates that transmission of the communication frame has ended (terminated normally or suspended). 2. indicates that setting of the transmission data has been completed with the current tbf. y n 0 1 10 or 11 00 start trcf? read str tfl? | ? | + 1 tbf ? transmission data (i-th byte) end 1 note 1 end 2 note 2 mtrqf (strqf) ? 0 trrq ? 0 ; transmission terminated normally or suspended? i > number of bytes in tranmission data www.datasheet.in
m pD72042 81 data sheet s14870ej1v0ds00 6.4.7 reception processing routine this routine is executed when rerq has been set by the interrupt routine. fig. 6-12 shows the flow of the reception processing routine. fig. 6-12 flow of reception processing routine notes 1. indicates that reception of the communication frame has ended (terminated normally or suspended). 2. indicates that reading of the reception data has been completed with the current rbf. y n 00 10 or 11 start read rbf j>size r ? j ? j + 1 recf r ? end 2 note 2 end 1 note 1 ; initialize j. ; reception terminated normally or suspended? j ? 1 increment pr www.datasheet.in
m pD72042 82 data sheet s14870ej1v0ds00 7. electrical characteristics absolute maximum ratings (t a = 25 c) parameter symbol conditions rated value unit supply voltage v dd , av dd | v dd C av dd | < 0.5 v C0.5 to +7.0 v input voltage for logic section v i C0.5 to v dd + 0.3 v output voltage for logic section v o C0.5 to v dd + 0.3 v bus input voltage v bi C0.5 to +6.0 v bus output voltage v bo C0.5 to +6.0 v operating ambient temperature t a C40 to +85 c storage temperature t stg C65 to +150 c caution absolute maximum ratings are rated values beyond which physical damage may be caused to the unit; if any of the parameters in the table above exceeds its rated value, even momentarily, the performance and/or reliability of the product may deteriorate. therefore, never exceed the products rated values. dc characteristics (t a = C40 to +85 c, v dd = 5 v 10%) parameter symbol conditions min. typ. max. unit input high voltage v ih 0.8v dd v dd v input low voltage v il 0 0.2v dd v output high voltage v oh i oh = C400 m a 0.7v dd v output low voltage v ol i ol = 2.5 ma 0.4 v input leakage current, high i lih v i = v dd 10 m a input leakage current, low i lil v i = 0 v C10 m a output leakage current, high i loh v o = v dd 10 m a output leakage current, low i lol v o = 0 v C10 m a supply current (normal i dd1 3.5 10 ma operation mode) supply current (standby mode) i dd2 50 m a capacitance characteristics (t a = 25 c, v dd = 0 v) parameter symbol conditions min. typ. max. unit input capacitance c i 15 pf i/o capacitance c io 15 pf f c = 1 mhz excluding the bus+ and bus- pins. 0 v for pins others than the measured pins. www.datasheet.in
m pD72042 83 data sheet s14870ej1v0ds00 ac characteristics (t a = C40 to +85 c, v dd = 5 v 10%) parameter symbol conditions min. typ. max. unit system clock 5.91 6.00 6.09 mhz sck cycle time t kcy 0.8 m s sck high-level width t kh 0.4 m s sck low-level width t kl 0.4 m s si (sio) note 1 setup time t sik referred to sck - 100 ns si (sio) note 1 hold time t ksi referred to sck - 400 ns so (sio) note 2 output delay t kso referred to sck 300 ns cs, c/d setup time t sa referred to sck 50 ns cs, c/d hold time t ha referred to sck - 400 ns irq output high-level width 811 m s reset low-level width 6 m s serial transfer timing notes 1. for 3-wire serial i/o: si for 2-wire serial i/o: sio 2. for 3-wire serial i/o: so for 2-wire serial i/o: sio t sa t ha t kcy t kl t kh t ksi t sik t kso cs, c/d sck si (sio) note 1 so (sio) note 2 input data output data www.datasheet.in
m pD72042 84 data sheet s14870ej1v0ds00 oscillator circuit (external system clock) caution when using system clock oscillator, wire the portion enclosed in broken lines in the figure as follows to avoid adverse influences on the wiring capacitance: ? keep the wiring length as short as possible. ? do not cross the wiring over the other signal lines. ? do not route the wiring in the vicinity of lines through which a high fluctuating current flows. ? always keep the ground point of the capacitor of the oscillator circuit at the same potential as gnd. ? do not connect the power source pattern through which a high current flows. ? do not extract signals from the oscillator. iebus driver/receiver characteristics (t a = C40 to +85 c, v dd = 5 v 10%) parameter symbol conditions min. typ. max. unit output high voltage i on r l = 60 w 5% 2.73 6.22 ma output low voltage i ol 1.0 m a common mode output voltage v ocom for high and low levels xC0.25 1/2v dd x+0.25 v x = 1/2v dd input high voltage v ih 120 mv input low voltage v il 20.0 mv input hysteresis voltage v ihys 25 mv common mode input voltage, high v ihcom 1.00 v dd C1.0 v common mode input voltage, low v ilcom 0v dd v driver output resistance r o between bus+ and busC 100 k w driver output capacitance c o 25 pf receiver input capacitance c i 25 pf between bus+ and busC, between bus+ and gnd, and between busC and gnd x1 xo c1 c2 gnd www.datasheet.in
m pD72042 85 data sheet s14870ej1v0ds00 circuit connected to iebus remark terminating resistor r l = 120 w 5% load capacitor c g please use the capacitor on the bus line under 7000 pf (between the bus+ pin and busC pin) therefore, the total load capacitance c t between the bus+ pin and busC pin is as follows. c t = n 1 c g + c w c w : wiring capacitance s 2 cautions 1. the circuit constants in the above figure are applied when each unit connected to the iebus line uses the m pD72042. 2. do not insert inductive parts into the bus line. m pD72042 bus + c g c g r l r l bus - www.datasheet.in
m pD72042 86 data sheet s14870ej1v0ds00 8. package drawing note each lead centerline is located within 0.12 mm of its true position (t.p.) at maximum material condition. a b n e detail of lead end k l p h g f i d 18 16 9 m s s c m j 16-pin plastic sop (9.53 mm (375)) item b c i a d e f g h j m millimeters 1.27 (t.p.) 0.805 max. 7.2 0.2 10.2 0.26 0.125 0.075 0.42 2.9 max. 10.3 0.3 2.50 0.2 + 0.08 - 0.07 1.6 0.2 0.12 0.10 n k l 0.17 + 0.08 - 0.07 0.8 0.2 p3 + 7 - 3 p16gt-50-375b-2 www.datasheet.in
m pD72042 87 data sheet s14870ej1v0ds00 9. recommended soldering conditions when soldering this product, it is highly recommended to observe the conditions as shown below. if other soldering processes are used, or if the soldering is performed under different conditions, please make sure to consult with our sales offices. for more details, refer to our document semiconductor device mounting technology manual (c10535e) . surface mount devices m pD72042gt: 16-pin plastic sop (9.53 mm (375)) process conditions symbol infrared ray reflow peak temperature: 235 c or below (package surface temperature), ir35-00-2 reflow time: 30 seconds or less (at 210 c or higher), maximum number of reflow processes: 2 times. vps peak temperature: 215 c or below (package surface temperature), vp15-00-2 reflow time: 40 seconds or less (at 200 c or higher), maximum number of reflow processes: 2 times. wave soldering solder temperature: 260 c or below, flow time: 10 seconds or less, ws60-00-1 maximum number of flow processes: 1 time, pre-heating temperature: 120 c or below (package surface temperature). partial heating method pin temperature: 300 c or below, heat time: 3 seconds or less (per each side of the device). caution apply only one kind of soldering condition to a device, except for partial heating method, or the device will be damaged by heat stress. www.datasheet.in
m pD72042 88 data sheet s14870ej1v0ds00 appendix a main differences between m pD72042, m pD72042b, and m pd6708 item m pD72042a m pD72042b m pd6708 product oscillation frequency (f x ) 6 mhz 12 mhz operating voltage (v dd )5 v 10% operating ambient temperature (t a ) C40 to +85 c iebus communication mode mode 0, 1 mode 0, 1, 2 driver/receiver built-in protective register not reguired 180 w 5% not reguired transmission buffer 33 bytes 4 bytes reception buffer 40 bytes 20 bytes interface with microcomputer note serial interface (3-wire/2-wire) serial interface (3-wire) msb first lsb first msb first package 16-pin plastic sop (9.53 mm (375)) note the setting method for the commands, data, and related pins for the m pD72042 and m pD72042b differs from that for the m pd6708. appendix b iebus protocol analyzer naito densei co., ltd. offers an iebus protocol analyzer for monitoring communication on iebus and evaluating application systems. for details of its functions and to place an order, contact: naito densei machida mfg. co., ltd. 3-9-25, hisamoto, takatsu-ku kawasaki, kanagawa 213-0011, japan tel 044 (822) 3813 fax 044 (822) 3681 16-pin plastic sop (7.62 mm (300)) 16-pin plastic dip (7.62 mm (300)) www.datasheet.in
m pD72042 89 data sheet s14870ej1v0ds00 [memo] www.datasheet.in
m pD72042 90 data sheet s14870ej1v0ds00 [memo] www.datasheet.in
m pD72042 91 data sheet s14870ej1v0ds00 notes for cmos devices 1 precaution against esd for semiconductors note: strong electric field, when exposed to a mos device, can cause destruction of the gate oxide and ultimately degrade the device operation. steps must be taken to stop generation of static electricity as much as possible, and quickly dissipate it once, when it has occurred. environmental control must be adequate. when it is dry, humidifier should be used. it is recommended to avoid using insulators that easily build static electricity. semiconductor devices must be stored and transported in an anti-static container, static shielding bag or conductive material. all test and measurement tools including work bench and floor should be grounded. the operator should be grounded using wrist strap. semiconductor devices must not be touched with bare hands. similar precautions need to be taken for pw boards with semiconductor devices on it. 2 handling of unused input pins for cmos note: no connection for cmos device inputs can be cause of malfunction. if no connection is provided to the input pins, it is possible that an internal input level may be generated due to noise, etc., hence causing malfunction. cmos devices behave differently than bipolar or nmos devices. input levels of cmos devices must be fixed high or low by using a pull-up or pull-down circuitry. each unused pin should be connected to v dd or gnd with a resistor, if it is considered to have a possibility of being an output pin. all handling related to the unused pins must be judged device by device and related specifications governing the devices. 3 status before initialization of mos devices note: power-on does not necessarily define initial status of mos device. production process of mos does not define the initial operation status of the device. immediately after the power source is turned on, the devices with reset function have not yet been initialized. hence, power-on does not guarantee out-pin levels, i/o settings or contents of registers. device is not initialized until the reset signal is received. reset operation must be executed immediately after power-on for devices having reset function. www.datasheet.in
m pD72042 iebus and inter equipment are trademarks of nec corporation. m8e 00. 4 the information in this document is current as of may, 2000. the information is subject to change without notice. for actual design-in, refer to the latest publications of nec's data sheets or data books, etc., for the most up-to-date specifications of nec semiconductor products. not all products and/or types are available in every country. please check with an nec sales representative for availability and additional information. no part of this document may be copied or reproduced in any form or by any means without prior written consent of nec. nec assumes no responsibility for any errors that may appear in this document. nec does not assume any liability for infringement of patents, copyrights or other intellectual property rights of third parties by or arising from the use of nec semiconductor products listed in this document or any other liability arising from the use of such products. no license, express, implied or otherwise, is granted under any patents, copyrights or other intellectual property rights of nec or others. descriptions of circuits, software and other related information in this document are provided for illustrative purposes in semiconductor product operation and application examples. the incorporation of these circuits, software and information in the design of customer's equipment shall be done under the full responsibility of customer. nec assumes no responsibility for any losses incurred by customers or third parties arising from the use of these circuits, software and information. while nec endeavours to enhance the quality, reliability and safety of nec semiconductor products, customers agree and acknowledge that the possibility of defects thereof cannot be eliminated entirely. to minimize risks of damage to property or injury (including death) to persons arising from defects in nec semiconductor products, customers must incorporate sufficient safety measures in their design, such as redundancy, fire-containment, and anti-failure features. nec semiconductor products are classified into the following three quality grades: "standard", "special" and "specific". the "specific" quality grade applies only to semiconductor products developed based on a customer-designated "quality assurance program" for a specific application. the recommended applications of a semiconductor product depend on its quality grade, as indicated below. customers must check the quality grade of each semiconductor product before using it in a particular application. "standard": computers, office equipment, communications equipment, test and measurement equipment, audio and visual equipment, home electronic appliances, machine tools, personal electronic equipment and industrial robots "special": transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster systems, anti-crime systems, safety equipment and medical equipment (not specifically designed for life support) "specific": aircraft, aerospace equipment, submersible repeaters, nuclear reactor control systems, life support systems and medical equipment for life support, etc. the quality grade of nec semiconductor products is "standard" unless otherwise expressly specified in nec's data sheets or data books, etc. if customers wish to use nec semiconductor products in applications not intended by nec, they must contact an nec sales representative in advance to determine nec's willingness to support a given application. (note) (1) "nec" as used in this statement means nec corporation and also includes its majority-owned subsidiaries. (2) "nec semiconductor products" means any semiconductor product developed or manufactured by or for nec (as defined above). www.datasheet.in

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