Fujitsu F2MC-16LX MB90580 Series Hardware Manual page 196

13.5 Operation
(4) Slave receive
This mode is set when the slave unit receive control bits AH, BH, EH or FH from the master. The
sequences for operating as slave receive are described as below:
1. After the slave returns the acknowledge bit in telegraph length field, the number of receive data byte is
written in the telegraph length read register (DERR). At this moment, no interrupt occurs.
2. Following the telegraph length field is the data field, the master starts transmitting data and each
received data byte is stored in the read data buffer (RDB).
3. After eight bytes of data are received, the state code (9H) indicating slave receive buffer full is set in
ST3-0 of status register (STRL), and receive interrupt occurs. If the receive interrupt occurs, the RDB
can be read after the confirmation of buffer not empty.
4. When the last byte of data in one communication frame is received and stored in RDB, the state code
(AH) indicating slave receive ends normally is set in ST3-0 and receive interrupt occurs. This interrupt
will occur even thought the buffer is not full.
5. If error is occurred during reception or the maximium number of data byte has been re3ceived in one
commmunication frame, the slave cannot receive the number pf data byte specified in telegraph field
and communication is terminated.. The state code (BH) indicating slave receive ends without all data
are received is set in ST3-0, and receive interrupt occurs.
(5) Multiaddress receive
1. After the slave has received the telegraph length field, the number of receive data byte is written in the
telegraph length read register (DERR). At this moment, no interrupt occurs.
2. After the telegraph lenght field is received, each correctly received data byte is stored in the read data
buffer (RDB).
3. After eight bytes of data are received, the state code (DH) indicating multiaddress receive buffer full is
set in ST3-0 of status register (STRL), and receive interrupt occurs. If the receive interrupt occurs, the
RDB can be read after the confirmation of buffer not empty.
4. When the last byte of data in one communication frame is received and stored in RDB, the state code
(EH) indicating multiaddress receive ends normally is set in ST3-0 and receive interrupt occurs. This
interrupt will occur even thought the buffer is not full.
5. If error is occurred during reception or the maximium number of data byte has been received in one
communication frame, the slave cannot receive the number of data byte specified in telegraph field and
communication is terminated. The state code (FH) indicating multiaddress receive ends without all data
are received is set in ST3-0, and receive interrupt occurs.
For detail description on ST3-0, please refer to Table 13.5.2a.
176 Chapter 13: IE Bus MB90580 Series