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CHAPTER 14 SERIAL INTERFACE (SIO3)
Preliminary User’s Manual U16035EJ1V0UM
Address: FFB0H (SIO30), FFB8H (SIO31) After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
CSIM3n
CSIE3n
0
0
0
0
MODEn
SCL3n1
SCL3n0
CSIE3n
Enable/disable specification for SIO3n
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
MODEn
Transfer operation modes and flags
Operation Mode
Transfer Start Trigger
SO3n output
0
Transmit/transmit and receive mode
Write to SIO3n
Normal output
1
Receive-only mode
Read from SIO3n
Fixed at low level
SCL3n1
SCL3n0
Clock selection
0
0
External clock input to SCK3n
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 CSIE3n = 0 (SIO3n operation stop status), the pins SI3n, SO3n, and SCK3n can be used for
port functions.
2.
When CSIE3n = 1 (SIO3n operation enabled status), the SI3n pin can be used as a port pin if only
the transmit function is used, and the SO3n pin can be used as a port pin if only the receive-only mode
is used.
Remarks 1.
n = 0, 1
2.
f
X
: Main system clock oscillation frequency
3.
Figures in parentheses are for operation with f
X
= 8.38 MHz.