MITSUBISHI MICROCOMPUTERS
M37274EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
Serial I/O Mode Register
b7b6 b5b4b3 b2b1b0
0 0
Serial I/O mode register (SM) [Address 021316]
B
Name
Functions
R W
R W
After reset
Internal synchronous
clock selection bits
(SM0, SM1)
0, 1
0
b1 b0
0
0
1
1
0: f(XIN)/4 or f(XCIN)/4
1: f(XIN)/16 or f(XCIN)/16
0: f(XIN)/32 or f(XCIN)/32
1: f(XIN)/64 or f(XCIN)/64
Synchronous clock
selection bit (SM2)
0
0
R W
R W
2
3
0: External clock
1: Internal clock
Port function
0: P1
1, P13
selection bit (SM3)
1: SCL1, SDA1
Port function
selection bit (SM4)
0: P1
1: SCL2, SDA2
2
, P1
4
0
0
R W
R W
4
5
0: LSB first
1: MSB first
Transfer direction
selection bit (SM5)
Fix these bits to “0.”
0
R W
6, 7
Fig. 21. Serial I/O Mode Register
27