UPD784938 Datasheet, PDF (495/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 20 IEBus CONTROLLER
• Communication error flag (IEERR) ... Bit 6
This flag detects an error during communication.
[Set/reset condition]
Set: Set if a timing error, parity error (except the data field), NACK reception (except the data field), or
underrun occurs
Reset: Through software manipulation
• Start interrupt flag (START) ... Bit 5
This flag indicates the interrupt during the ACK period of the slave address field.
[Set/reset condition]
Set: Set in the slave address field during the master request.
Set if there was a slave request from the master. (In the case of lock status, only if there was a slave
request from the lock request unit.)
Reset: Through software manipulation
• Status transmission flag (STATUS) ... Bit 4
This flag indicates that the master transmits a slave status or lock address (high-order 4 bits, low-order 8 bits) while
the unit serves as a slave.
[Set/reset condition]
Set: Set when “0H, 4H, 5H, or 6H” is received from the master in the control field while the unit serves as
a slave.
Reset: Through software manipulation
• Communication end flag (ENDTRNS) ... Bit 3
This flag indicates whether communication has been completed by the number of transmit bytes set by the telegraph
length field.
[Set/reset condition]
Set: When the count value of the SCR counter has reached 0.
Reset: When any of the master request flag, slave transmission enable flag, or slave reception enable flag is
set.
• Frame end flag (ENDFRAM) ... Bit 2
This flag indicates whether communication of the maximum number of transmit bytes (32 bytes) specified by each
communication mode is completed.
[Set/reset condition]
Set: When the count value of the CCR has reached 0.
Reset: When any of the master request fag, slave transmission enable flag, or slave reception enable flag is
set
Preliminary User’s Manual U13987EJ1V0UM00
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