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CHAPTER 17
IEBus CONTROLLER (
PD178096A, 178098A, 178F098 ONLY)
User’s Manual U12790EJ2V0UD
(b) Arbitration result flag (ARBIT)...Bit 5
A flag that indicates the result of arbitration.
<Set/reset conditions>
Set:
When the data output by the IEBus unit during the arbitration period does not match the bus line
data after the master request.
Reset: By the start bit timing.
Cautions 1. The timing at which the arbitration result flag (ARBIT) is reset differs depending on
whether the unit outputs a start bit.
If start bit is output: The flag is reset at the output start timing.
If start bit is not output: The flag is reset at the detection timing of the start bit (approx.
160
s after output)
2. The flag is reset at the detection timing of the start bit if the other unit outputs the start
bit earlier and the local unit does not output the start bit after the master request.
(c) Broadcast communication flag (ALLTRNS)...Bit 4
A flag that indicates whether the unit is performing broadcast communication. The contents of the flag are
updated in the broadcast field of each frame.
Except for initialization (reset) by system reset, the set/reset conditions vary depending on the receive data
of the broadcast field bit.
<Set/reset conditions>
Set:
When “Broadcast” is received by the broadcast field
Reset: When “individual” is received by the broadcast field, or upon the input of a system reset.
Caution The broadcast communication flag is updated regardless of whether the IEBus is the
communication target or not.
Figure 17-23. Example of broadcast Communication Flag Operation
(d) ACK transmission flag (ACK)...Bit 3
A flag that indicates whether ACK has been transmitted in the ACK period of the ACK field when the IEBus
is a receiving unit. The contents of the flag are updated in the ACK period of each frame. However, if the
internal circuit is initialized by the occurrence of a parity error, etc., the contents are not updated in the ACK
period of that field.
Broadcast
communication flag
Reset
Set
Not reset
by start bit
IEBus sequence
Start
M11
Broad-
cast
M10
M11
Individual
M10
Start