NEC PM: Port mode register

410
CHAPTER 18 SERIAL INTERFACE CHANNEL 1
Notes 1. If the external clock input has been selected with CSIM11 set to 0, set bit 1 (BUSY 1) and bit
2 (STRB) of the automatic data transmit/receive control register (ADTC) to 0, 0.
2. Can be used freely as port function.
3. Can be used as P20 (CMOS input/output) when only transmitter is used (clear bit 7 (RE) of
ADTC to 0).
Remark ×: Don't care
PM××: Port mode register
P×× : Port output latch
Operation
enable
6<5>43210<7>
Symbol
CSIM1 CSIE1 DIR ATE 0 0 0
CSIM11 CSIM10
CSIM11
0
1
Serial Interface Channel 1 Clock Selection
Clock externally input to SCK1 pin
Note 1
8-bit timer register 2 (TM2) output
SCK1
(Input)
1 Clock specified with bits 4 to 7 of timer clock select register 3 (TCL3)
CSIE1
0
CSIM10
×
0
1
FF68H 00H R/W
Address After Reset R/W
CSIM11
P20 PM21 P21 PM22
Note 3
Shift Register 1
Operation
Serial Clock Counter
Operation Control
SI1/P20 Pin
Function
SCK1/P22
Pin Function
×
1
0
1
0
×00
1×
1
Note 2Note 2 Note 2Note 2
Count
operation
SI1
(Input)
×××××Operation
stop
Clear P20 (CMOS
input/output) P22 (CMOS input/output)
ATE
0
Serial Interface Channel 1 Operating Mode Selection
3-wire serial I/O mode
DIR
0
1
Start Bit
MSB
LSB
SI1 Pin Function
SI1/P20
(Input)
SO1 Pin Function
SO1
(CMOS output)
×
PM20
SO1/P21 Pin
Function
SO1 (CMOS
output)
P21 (CMOS
input/output)
SCK1
(CMOS
output)
1
Note 2
Note 2
Note 3Note 3
P22
1 3-wire serial I/O mode with automatic transmit/receive function