Datasheet

Section 14 IEBus™ Controller (IEB) [H8S/2258 Group]
Rev. 6.00 Mar. 18, 2010 Page 501 of 982
REJ09B0054-0600
Bit Bit Name
Initial
Value
R/W Description
7 to 3 ⎯ All 0 ⎯ Reserved
The read value is undefined. In order to avoid malfunction,
do not use bit manipulation instructions. These bits cannot
be modified.
2
1
0
CMD2
CMD1
CMD0
0
0
0
W
W
W
Command Bits
These bits issue a command to control IEB
communications. When the CMX flag in IEFLG is set after
the command issuance, the command is indicated to be in
execution. When the CMX flag becomes 0, the operation
state is entered. These bits are read as 0. The read value
is undefined. Do not use a bit manipulation instruction that
causes malfunction.
000: No operation. Operation is not affected.
001: Unlock (required from other units)
*
1
010: Requires communications as the master
011: Stops master communications
*
2
100: Undefined bits. Operation is not affected by this
command.
101: Requires data transfer from the slave.
110: Stops data transfer from the slave
*
3
.
111: Undefined bits. Operation is not affected by this
command.
Notes: 1. Do not execute this command in slave communications. Execute this command after
slave communications ends or in master communications. If this command is issued in
slave communications, this command is ignored.
2. This command is valid during master communications (MRQ = 1). In other states, this
command issuance is ignored. If this command is issued in master communications, the
communications controller immediately enters the wait state. At this time, the issued
master transmission request ends (MRQ = 0).
3. This command is valid during slave communications (SRQ = 1). In other states, this
command issuance is ignored. Once this command was issued in slave transmission,
the SRQ flag is 0 before slave transmission. Therefore, a transmit request from the
master is not responded. If a transmit request is issued during slave transmission, the
transmission stops and the wait state is entered (SRQ = 0).