
R8C/14 Group, R8C/15 Group 15. Clock Synchronous Serial I/O with Chip Select (SSU)
Rev.2.10 Jan 19, 2006 Page 153 of 253
REJ09B0164-0210
15.4 Communication Modes and Pin Functions
SSU switches functions of the I/O pin in each communication mode according to the setting of the
MSS bit in the SSCRH register and the RE and TE bits in the SSER register. Table 15.3 shows the
Association between Communication Modes and I/O Pins.
NOTES:
1. This pin can be used as programmable I/O port.
2. Do not set both the TE and RE bits to “1” in 4-wire bus (bidirectional) communication mode.
SSUMS and BIDE : Bits in SSMR2 register
MSS : Bit in SSCRH register
TE and RE : Bits in SSER register
Table 15.3 Association between Communication Modes and I/O Pins
Communication Mode
Bit Setting Pin State
SSUMS BIDE MSS TE RE SSI SSO SSCK
Clock Synchronous
Communication Mode
0Disabled001Input
−
(1)
Input
10
−
(1)
Output Input
1 Input Output Input
101Input
−
(1)
Output
10
−
(1)
Output Output
1 Input Output Output
4-Wire Bus
Communication Mode
10 001
−
(1)
Input Input
1 0 Output
−
(1)
Input
1 Output Input Input
101Input
−
(1)
Output
10
−
(1)
Output Output
1 Input Output Output
4-Wire Bus
(Bidirectional)
Communication Mode
(2)
11 001
−
(1)
Input Input
10
−
(1)
Output Input
101
−
(1)
Input Output
10
−
(1)
Output Output
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