Transfer Data - Renesas RZ/A Series User Manual

RZ/A1L Group, RZ/A1LU Group, RZ/A1LC Group
Cautions
22.7.7

Transfer data

R01UH0437EJ0600 Rev.6.00
Jan 29, 2021
1. The ACK signal is always returned when the control data of the slave status
request is received, if the IEBBnSTXE bit = 0.
2. The NACK signal is returned by the acknowledge bit in the control field
when the control data for data/command writing is received, even if the
IEBBnSRXE bit = 0.
Slave reception can be disabled (communication stopped) by the
IEBBnSRXE bit only in the case of individual communication. In the case of
broadcast communication, communication is maintained and the data
interrupt (IEBBTD) or completion interrupt (IEBBTSTA) is generated.
(c) Last acknowledge bit of message length field
The last acknowledge bit of the message length field serves as a NACK signal in any
of the following cases, and transmission is stopped.
• If the parity of the message length bit is incorrect
• If a timing error occurs
(d) Last acknowledge bit of the data field
The last acknowledge bit of the data field serves as a NACK signal in any of the
following cases, and transmission is stopped.
• If the parity of the data bit is incorrect
• If a timing error occurs after the preceding acknowledge bit has been transmitted
• If the received data is stored in the IEBBnDR register and no more data can be
a
received
a)
In this case, when the communication executed is individual communication, if the
maximum number of transmit bytes is within the value that can be transmitted in
one frame, the transmission side executes transmission of that data field again. For
broadcast communication, the transmission side does not execute transmission
again, a communication error occurs on the reception side and reception stops.
(1) Slave status
The master unit can learn why the slave unit did not return the ACK signal by reading
the slave status.
The slave status is determined according to the result of the last communication the
slave unit has executed.
All the slave units can supply information on the slave status.
The configuration of the slave status is shown below.
a
22. IEBus Controller
22-124