Renesas H8S/2100 Series Hardware Manual page 541

Bit Bit Name
0 ACKB
Note: * Only 0 can be written to clear the flag.
Initial
Value R/W Description
Acknowledge Bit
0 R/W
Stores acknowledge data.
The bit function varies depending on transmit mode and
receive mode.
Transmit mode:
Holds the acknowledge data returned by the receiving
device.
[Setting condition]
•
When 1 is received as the acknowledge bit when
ACKE = 1 in transmit mode
[Clearing conditions]
•
When 0 is received as the acknowledge bit when
ACKE = 1 in transmit mode
•
When 0 is written to the ACKE bit
Receive mode:
Sets the acknowledge data to be returned to the
transmitting device.
0: Returns 0 as acknowledge data after data reception
1: Returns 1 as acknowledge data after data reception
When this bit is read, the value loaded from the bus line
(returned by the receiving device) is read in transmission
(when TRS = 1). In reception (when TRS = 0), the value
set by internal software is read.
When this bit is written, acknowledge data that is returned
after receiving is rewritten regardless of the TRS value.
Note: When, in transmit mode, this bit has been
overwritten by a bit manipulation instruction with a value
other than that of the ACKB flag in ICSR, the value of the
ACKB bit as the acknowledge data setting for receive
mode is overwritten by this value. Thus, always reset the
acknowledge data when switching to receive mode.
Write 0 to the ACKE bit to clear the ACKB flag to 0 in the
following cases:
in master mode—before transmission is ended and a stop
condition is generated; and
in slave mode—before transmission is ended and SDA is
released to allow a master device to issue a stop
condition.
2
Section 17 I C Bus Interface (IIC)
Rev. 1.00 May 09, 2008 Page 515 of 954
REJ09B0462-0100