Datasheet

Section 16 I
2
C Bus Interface [H8S/2138 Group Option]
Rev. 4.00 Jun 06, 2006 page 470 of 1004
REJ09B0301-0400
Bit 5 Bit 4
MST TRS Operating Mode
0 0 Slave receive mode (Initial value)
1 Slave transmit mode
1 0 Master receive mode
1 Master transmit mode
Bit 5
MST Description
0 Slave mode (Initial value)
[Clearing conditions]
1. When 0 is written by software
2. When bus arbitration is lost after transmission is started in I
2
C bus format master
mode
1 Master mode
[Setting conditions]
1. When 1 is written by software (in cases other than clearing condition 2)
2. When 1 is written in MST after reading MST = 0 (in case of clearing condition 2)
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
4. When the SW bit in DDCSWR changes from 1 to 0
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 a 1 is received as the R/W bit of the first frame in I
2
C bus format slave mode