Datasheet

Section 18 I
2
C Bus Interface [Option]
(This function is not available in the H8S/2695)
Page 852 of 1434 R01UH0166EJ0600 Rev. 6.00
Mar 02, 2011
H8S/2633 Group, H8S/2633 F-ZTAT
TM
,
H8S/2633R F-ZTAT
TM
, H8S/2695
Bit 4
TRS Description
0 Receive mode (Initial value)
[Clearing conditions]
1. When 0 is written by software (in cases other than setting condition 3)
2. When 0 is written in TRS after reading TRS = 1 (in case of clearing condition 3)
3. When bus arbitration is lost after transmission is started in I
2
C bus format master
mode
1 Transmit mode
[Setting conditions]
1. When 1 is written by software (in cases other than clearing conditions 3 and 4)
2. When 1 is written in TRS after reading TRS = 0 (in case of clearing conditions 3
and 4)
3. When 1 is received as the R/W bit of the first frame in I
2
C bus format slave mode
Bit 3—Acknowledge Bit Judgement Selection (ACKE): Specifies whether the value of the
acknowledge bit returned from the receiving device when using the I
2
C bus format is to be ignored
and continuous transfer is performed, or transfer is to be aborted and error handling, etc.,
performed if the acknowledge bit is 1. When the ACKE bit is 0, the value of the received
acknowledge bit is not indicated by the ACKB bit, which is always 0.
In the H8S/2633 Group, the DTC
*
can be used to perform continuous transfer. The DTC
*
is
activated when the IRTR interrupt flag is set to 1 (IRTR is one of two interrupt flags, the other
being IRIC). When the ACKE bit is 0, the TDRE, IRIC, and IRTR flags are set on completion of
data transmission, regardless of the value of the acknowledge bit. When the ACKE bit is 1, the
TDRE, IRIC, and IRTR flags are set on completion of data transmission when the acknowledge
bit is 0, and the IRIC flag alone is set on completion of data transmission when the acknowledge
bit is 1.
When the DTC
*
is activated, the TDRE, IRIC, and IRTR flags are cleared to 0 after the specified
number of data transfers have been executed. Consequently, interrupts are not generated during
continuous data transfer, but if data transmission is completed with a 1 acknowledge bit when the
ACKE bit is set to 1, the DTC
*
is not activated and an interrupt is generated, if enabled.
Depending on the receiving device, the acknowledge bit may be significant, in indicating
completion of processing of the received data, for instance, or may be fixed at 1 and have no
significance.
Note: * The DTC function is not available in the H8S/2695.