5 adc pin select register (adcchn) – NEC PD17062 User Manual
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µ
PD17062
b
3
b
2
b
1
#0
(MSB)
(LSB)
(RF : 21H)
ADCCMP
ADCCH2
ADCCH1
ADCCH0
Selected pin
0
0
0
ADC
0
0
0
1
P1C
3
/ADC
1
0
1
0
P0D
0
/ADC
2
0
1
1
P0D
1
/ADC
3
1
0
0
P0D
2
/ADC
4
1
0
1
P0D
3
/ADC
5
1
1
0
No corresponding pin
(do not set)
1
1
1
19.5 ADC PIN SELECT REGISTER (ADCCHn)
The ADCCHn register selects an A/D converter input pin. It is mapped at the upper 3 bits of the register
file at address 21H. Table 19-2 lists the relationships between the ADCCHn and the actually selected pins.
Table 19-2 ADC Pin Selection
When using P1C
3
/ADC
1
as the A/D converter, specify the P1C as an input port.
The P0D
0
/ADC
2
to P0D
3
/ADC
5
pins are internally equipped with pull-down resistors, but the pull-down
resistors are disconnected when they are selected as the A/D converter.
If P1C and P0D pins selected as the A/D converter are accessed as ports, “0” is read out.