MOS Integrated Circuit Data Sheet

236
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
110
No corresponding pin
(do not set)
111
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 P1C3/ADC1 as the A/D converter, specify the P1C as an input port.
The P0D
0/ADC2 to P0D3/ADC5 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.