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CHAPTER 14 SERIAL INTERFACE SIO3
User’s Manual U15798EJ2V0UD
Figure 14-2. Format of Serial Operation Mode Register 3 (CSIM3)
Address: FFAFH After reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
CSIM3
CSIE3
0
0
0
0
MODE
SCL31
SCL30
CSIE3
Enable/disable specification for SIO3
Shift register operation
Serial counter
Port
0
Operation stop
Clear
Port function
Note 1
1
Operation enable
Count operation enable
Serial fu port function
Note 2
MODE
Transfer operation modes and flags
Operation mode
Transfer start trigger
SO3/P21 pin function
0
Transmit/transmit and receive mode
Write to SIO3
SO3
1
Receive-only mode
Read from SIO3
P21
SCL31
SCL30
Clock selection
0
0
External clock input to SCK3
0
1
f
X
/2
3
(1.25 MHz)
1
0
f
X
/2
5
(312.5 kHz)
1
1
f
X
/2
7
(78.125 kHz)
Notes 1.
When CSIE3 = 0 (SIO3 operation stop status), the SI3, SO3, and SCK3 pins can be used for port
functions.
2.
When CSIE3 = 1 (SIO3 operation enabled status), the SI3 pin can be used as a port pin if only the
transmit function is used, and the SO3 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
= 10 MHz.
Содержание mPD780344 Series
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