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CHAPTER 14 SERIAL INTERFACE (SIO3)
Preliminary User’s Manual U16035EJ1V0UM
Figure 14-3. Format Serial Operation Mode Register 31 (CSIM31)
Address: FFB8H After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
CSIM31
CSIE31
0
0
0
0
MODE1
SCL311
SCL310
CSIE31
Enable/disable specification for SIO31
Shift register operation
Serial counter
Port
0
Operation disabled
Clear
Port function
Note 1
1
Operation enabled
Count operation enabled
Serial fu port function
Note 2
MODE1
Transfer operation modes and flags
Operation mode
Transfer start trigger
SO31 output
0
Transmit/transmit and receive mode
Write to SIO31
Normal output
1
Receive-only mode
Read from SIO31
Fixed at low level
SCL311
SCL310
Clock selection
0
0
External clock input to SCK31
0
1
f
X
/2
3
(1.05 MHz)
1
0
f
X
/2
4
(524 kHz)
1
1
f
X
/2
5
(262 kHz)
Notes 1.
When CSIE31 = 0 (SIO31 operation stop status), the pins SI31, SO31, and SCK31 can be used for
port functions.
2.
When CSIE31 = 1 (SIO31 operation enabled status), the SI31 pin can be used as a port pin if only
the transmit function is used, and the SO31 pin can be used as a port pin if only the receive-only mode
is used.
Remarks 1.
f
X
: Main system clock oscillation frequency
2.
Figures in parentheses are for operation with f
X
= 8.38 MHz.
