UPD784938 Datasheet, PDF (485/733 Pages) NEC – 16-Bit Single-Chip Microcontrollers

CHAPTER 20 IEBus CONTROLLER
• Communication enable flag (ENIEBUS) ... Bit 7
[Set/reset condition]
Set: Through software manipulation
Reset: Through software manipulation
Caution Before setting this flag, the following registers for communication must be set.
During master transmission
During master reception
During slave transmission
During slave reception
UAR
• Master request flag (MSTRQ) ... Bit 6
[Set/reset condition]
Set: Through software manipulation
Reset: Through hardware at the end of the arbitration period
Caution Make a remaster request through software processing in case the unit loses in contention.
• Broadcasting request flag (ALLRQ) ... Bit 5
[Set/reset condition]
Set: Through software manipulation
Reset: Through software manipulation
Caution Be sure to set this flag to request broadcasting communication, and set bit 6.
• Slave transmission enable flag (ENSLVTX) ... Bit 4
[Set/reset condition]
Set: Through software manipulation
Reset: Through software manipulation
Cautions 1. Clear this flag before setting the master request flag during master request. If a slave
transmission request is made by the master with this flag not set during slave, or if the
disabled status is to be returned to the enabled status, the next new frame and those that
follow become valid.
2. When ENSLVTX is not set, upon reception of data/command write control data “3H, 7H”,
the acknowledge bit of the control field returns NACK.
3. Even if ENSLVTX has been reset, when slave status request control data is returned, a status
interrupt (INTIE2) is generated and communication is continued.
• Slave reception enable flag (ENSLVRX) ... Bit 3
[Set/reset condition]
Set: Through software manipulation
Reset: Through software manipulation
Preliminary User’s Manual U13987EJ1V0UM00
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