4 serial interface 1a0 operation, 1 operation stop mode – NEC PD78F9488 User Manual
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CHAPTER 12 SERIAL INTERFACE 1A0
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User’s Manual U15331EJ4V1UD
12.4 Serial Interface 1A0 Operation
Serial interface 1A0 provides the following three modes.
• Operation stop mode
• 3-wire serial I/O mode
• 3-wire serial I/O mode with automatic transmit/receive function
12.4.1 Operation stop mode
In operation stop mode, serial transfer is not executed, thereby reducing the power consumption. The P23/SCK10,
P24/SO10, and P25/SI10 pins can be used as normal I/O ports.
(1) Register
setting
Operation stop mode is set by serial operation mode register 1A0 (CSIM1A0).
(a) Serial operation mode register 1A0 (CSIM1A0)
CSIM1A0 is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input clears CSIM1A0 to 00H.
Symbol
<7> 6 <5>
<4> 3 2 1 0
Address
After
reset
R/W
CSIM1A0 CSIE10 DIR10 ATE0 LSCK10
0
0
SCL101 SCL100 FF78H
00H
R/W
Specification of operation enable/disable
CSIE10
Shift register operation
Serial counter
Port
Note
0
Operation stopped
Cleared
Port function
1
Operation enabled
Count operation enabled
Serial function + port function
Note When CSIE10 = 0 (SIO1A0 operation stop status), the SCK10/P23, SO10/P24, and SI10/P25 pins can
freely be used as port pins.