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CHAPTER 15 SERIAL INTERFACE CSI1
User’s Manual U15798EJ2V0UD
15.3 Registers to Control Serial Interface CSI1
Serial interface CSI1 is controlled by the following two registers.
• Serial operation mode register 1 (CSIM1)
• Serial clock select register 1 (CSIC1)
(1) Serial operation mode register 1 (CSIM1)
This register is used to select an operation mode and enable or disable the operation.
This register can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets the value of this register to 00H.
Figure 15-2. Format of Serial Operation Mode Register 1 (CSIM1)
Address: FFB0H After reset: 00H R/W
Note 1
Symbol
7
6
5
4
3
2
1
0
CSIM1
CSIE1
TRMD1
0
DIR1
0
0
0
CSOT1
CSIE1
Operation control in 3-wire serial I/O mode
0
Stops operation (SI1/P23, SO1/P24, and SCK1/P25 pins can be used as general-purpose port
pins).
1
Enables operation (SI1/P23, SO1/P24, and SCK1/P25 pins can be used in 3-wire serial I/O mode).
TRMD1
Note 2
Transmit/receive mode selection
0
Note 3
Receive mode (transmission disabled).
1
Transmit/receive mode
DIR1
Note 4
First bit specification
0
MSB
1
LSB
CSOT1
Note 5
Operation mode flag
0
Communication is stopped.
1
Communication is in progress.
Notes 1.
Bit 0 is a read-only bit.
2.
Do not rewrite TRMD1 when CSOT1 = 1 (during serial communication).
3.
The SO1 output is fixed to the low level when TRMD1 is 0. Reception is started when data is read
from SIO1.
4.
Do not overwrite these bits when CSOT1 = 1 (during serial communication).
5.
CSOT1 is cleared if CSIE1 is cleared to 0 (operation stops).
Caution Be sure to set bit 5 to 0.
Содержание mPD780344 Series
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