NEC PD17062 Manuale Utente

µ

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

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.

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.