185
CHAPTER 15 SERIAL INTERFACE SIO3
15.3 SIO3 Control Register
The SIO3 uses the following type of register for control functions.
• Serial operation mode register (CSIM)
(1) Serial operation mode register (CSIM)
This register is used to enable or disable SIO3’s serial clock, operation modes, and specific operations.
CSIM is set with a 1-bit or 8-bit memory manipulation instruction.
The RESET input resets the value to 00H.
Caution
In the 3-wire serial I/O mode, set the port mode register (PM5X) as follows. Besides that,
set all output latches to 0.
• When serial clock output (Master transmit or Master receive)
Set P50 (SCK) to the output mode (PM50 = 0)
• When serial clock input (Slave transmit or Slave receive)
Set P50 to the input mode (PM50 = 1)
• When transmit/transceive mode
Set P51 (SO) to the output mode (PM51 = 0)
• When receive mode
Set P52 (SI) to the input mode (PM52 = 1)
Figure 15-2. Serial Operation Mode Register (CSIM) Format
Address: FF84H After Reset: 00H R/W
Symbol
7
6
5
4
3
2
1
0
CSIM
CSIE
0
0
0
0
MODE
SCL1
SCL0
CSIE
SIO3 Operation Enable/Disable Specification
Shift Register Operation
0
Operation disable
1
Operation enable
MODE
Transfer Operation Mode Flag
Operation Mode
0
Transmit or transmit/receive mode
1
Receive-only mode
SCL1
SCL0
Clock Selection (f
X
= 8.38 MHz)
0
0
External clock input
0
1
f
X
/2
2
1
0
f
X
/2
3
1
1
f
X
/2
4
Caution
Bits 3 to 6 must be set to 0.
Summary of Contents for mPD780973 Series
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