NEC uPD78056Y - Manual (Page 301)

301
CHAPTER 16 SERIAL INTERFACE CHANNEL 0 (
µ
PD78054 Subseries)
16.4 Serial Interface Channel 0 Operations
The following four operating modes are available to the serial interface channel 0.
• Operation stop mode
• 3-wire serial I/O mode
• SBI mode
• 2-wire serial I/O mode
16.4.1 Operation stop mode
Serial transfer is not carried out in the operation stop mode. Thus, power consumption can be reduced. The serial
I/O shift register 0 (SIO0) does not carry out shift operation either and thus it can be used as ordinary 8-bit register.
In the operation stop mode, the P25/SI0/SB0, P26/SO0/SB1 and P27/SCK0 pins can be used as ordinary input/
output ports.
(1) Register setting
The operation stop mode is set with the serial operating mode register 0 (CSIM0).
CSIM0 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets CSIM0 to 00H.
<6> <5> 4 3 2 1 0 <7>
Symbol
CSIM0 CSIE0 COI WUP CSIM04 CSIM03 CSIM02 CSIM01 CSIM00 FF60H 00H R/W
Address After Reset R/W
CSIE0
0
Serial Interface Channel 0 Operation Control
Operation stopped
Operation enabled
R/W
1