H8S2556 Datasheet, PDF (609/982 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer H8S Family/H8S/2500 Series

Section 17 IEBus™ Controller (IEB) [H8S/2552 Group]
Initial
Bit Bit Name 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
CMD2
0
W
Command Bits
1
CMD1
0
0
CMD0
0
W
These bits issue a command to control IEB
W
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. 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).
Rev.5.00 Sep. 27, 2007 Page 563 of 932
REJ09B0099-0500