R8C/36T-A Group
21. Clock Synchronous Serial Interface
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0240EJ0010 Rev.0.10
Page 471 of 728
Aug 05, 2011
21.2.10 SI Mode Register 2 (SIMR2)
In the SIMR2 register, the bit functions differ between the SSU and I2C bus functions.
21.2.10.1 SSU Function
Notes:
data I/O pins.
2. When using 4-wire bus communication mode, always use the SCS pin as N-channel open-drain output.
3. When the SCS pin is used as CMOS output, a conflict error may occur when SCS output is enabled. After the
error flag is cleared, set to master mode again to continue communication.
4. Set bits CSOS, SOOS, and SCKOS to 0 (CMOS output) when this module is not used.
5. Do not set bits CSOS, CSS0, and CSS1 simultaneously. When the SCS pin is selected, first set the CSOS bit
and then set bits CSS1 and CSS0 to 01b, 10b, or 11b. When the SCS pin is not selected, first set bits CSS1 and
CSS0 to 00b and then set the CSOS bit.
6. When the SOOS bit is 0, set the port direction register bits corresponding to pins SSI and SSO to 0 (input mode).
7. Do not set bits SCKOS and SCKS simultaneously. When the SSCK pin is selected, set the SCKOS bit before
setting the SCKS bit to 1 (functions as the serial clock pin). When the SSCK pin is not selected, set the SCKS bit
to 0 (function as a port) before setting the SCKOS bit.
8. When the MS bit is 0 (clock synchronous communication mode), the SCS pin functions as a port regardless of
the content of bits CSS0 and CSS1.
9. This bit functions as the SCS input pin before transfer starts.
10.The BIDE bit is disabled when the MS bit is 0 (clock synchronous communication mode).
Address 000EBh (SIMR2_0)
Bit
b7b6
b5b4b3
b2b1b0
Symbol
After Reset
0
000
0000
Bit
Symbol
Bit Name
Function
R/W
b0
MS
0: Clock synchronous communication mode
1: 4-wire bus communication mode
R/W
b1
CSOS
SCS pin open-drain output select bit
0: CMOS output
1: N-channel open-drain output
R/W
b2
SOOS
Serial data open-drain output select bit
1: N-channel open-drain output
R/W
b3
SCKOS
SSCK pin open-drain output select bit
0: CMOS output
1: N-channel open-drain output
R/W
b4
CSS0
b5 b4
0 0: Functions as a port
0 1: Functions as the SCS input pin
1 0: Functions as the SCS output pin
(9)1 1: Functions as the SCS output pin
(9)R/W
b5
CSS1
R/W
b6
SCKS
0: Functions as a port
1: Functions as the serial clock pin
R/W
b7
BIDE
Bidirectional mode enable bit
(1, 10)0: Standard mode (communication using two
pins for data input and data output)
1: Bidirectional mode (communication using
one pin for data input and data output)
R/W