CHAPTER 19 IEBus CONTROLLER (V850/SB2)
User’s Manual U13850EJ4V0UM
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(c) Last acknowledge bit of telegraph length field
The last acknowledge bit of the telegraph length field serves as NACK in any of the following cases, and
transmission is stopped.
•
If the parity of the telegraph length bit is incorrect
•
If a timing error occurs
(d) Last acknowledge bit of data field
The last acknowledge bit of the data field serves as NACK in any of the following cases, and
transmission is stopped.
•
If the parity of the data bit is incorrect
Note
•
If a timing error occurs after the preceeding acknowledge bit has been transmitted
•
If the receive data is stored in the IEBus data register (DR) and no more data can be received
Note
Note
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 broadcasting communication, the
transmission side does not execute transmission again, a communication error occurs on the
reception side and reception stops.
19.1.7 Transfer data
(1) Slave status
The master unit can learn why the slave unit did not return the acknowledge bit (ACK) 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.