Section 14 Synchronous Serial Communication Unit (SSU)
14.4.4
Communication Modes and Pin Functions
The SSU switches the input/output pin (SSI, SSO, SSCK, and SCS) functions according to the
communication modes and register settings. When a pin is used as an input pin, set the
corresponding bit in the input buffer control register (ICR) to 1. The relationship of
communication modes and input/output pin functions are shown in tables 14.2 to 14.4.
Table 14.4 Communication Modes and Pin States of SSI and SSO Pins
Communication
Mode
SSU communication
mode
SSU (bidirectional)
communication mode
Clock synchronous
communication mode
[Legend]
: Not used as SSU pin (can be used as I/O port)
Rev. 3.00 Mar. 14, 2006 Page 528 of 804
REJ09B0104-0300
Register Setting
SSUMS
BIDE
0
0
0
1
1
0
MSS
TE
0
0
1
1
0
1
0
0
1
1
0
1
0
0
1
1
0
1
Pin State
RE
SSI
1
0
Output
1
Output
1
Input
0
1
Input
1
0
1
0
1
Input
0
1
Input
1
Input
0
1
Input
SSO
Input
Input
Output
Output
Input
Output
Input
Output
Output
Output
Output
Output