
CHAPTER 18 IEBus CONTROLLER
User’s Manual U16541EJ4V0UD
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(a) Communication error flag (IEERR)...Bit 6
A flag that indicates a communication error has occurred.
When a communication error occurs, the
INTIE2 and INTERR interrupt request signals are generated.
<Set/clear conditions>
Set:
The flag is set (1) if a timing error, parity error (except in the data field), NACK reception error
(except in the data field), underrun error, overrun error (that occurs during broadcast
communication reception), or write error occurs.
Clear: By software
(b) Start interrupt flag (STARTF)...Bit 5
A flag that indicates the start interrupt. When a start interrupt occurs, the INTIE2 and INTSTA interrupt
request signals are generated.
<Set/clear conditions>
Set:
This flag is set (1) in the slave address field, upon a master request.
When IEBus is a slave unit, this flag is set (1) upon a request from the master (only if it was a slave
request in the locked state from the unit requesting a lock).
Clear: This flag is cleared (0) if the status transmission interrupt, communication end interrupt, frame end
interrupt, or INTIE1 interrupt request signal is generated.
(c) Status transmission flag (STATUSF)...Bit 4
A flag that indicates the master requested transmission of the slave status and lock address (higher 4 bits
and lower 8 bits) when the controller was serving as a slave.
<Set/clear conditions>
Set:
This flag is set (1) when 0H, 4H, 5H, or 6H is received in the control field from the master when the
IEBus is a slave unit.
Clear: This flag is cleared (0) if the start interrupt, communication end interrupt, frame end interrupt, or
INTIE1 interrupt request signal is generated.
(d) Communication end flag (ENDTRANS)...Bit 3
A flag that indicates whether communication ends after the number of bytes set in the telegraph length
field have been transferred.
When a communication error occurs, the INTIE2 and INTSTA interrupt
request signals are generated.
<Set/clear conditions>
Set:
This flag is set (1) when the count value of the SCR register is 00H.
Clear: This flag is cleared (0) if the start interrupt, status transmission interrupt, frame end interrupt (if the
communication end interrupt does not occur), or INTIE1 interrupt request signal is generated.