UPD17708 datasheet(194/356 Pages) NEC

No. de pieza	UPD17708

Descripción Electrónicos	4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DEDICATED HARDWARE FOR DIGITAL TUNING SYSTEM

PDF	356 Pages

Scroll/Zoom	100%

Fabricante Electrónico	NEC [NEC]

Página de inicio	http://www.nec.com/

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194 / 356 page

µPD17704, 17705, 17707, 17708, 17709

194

14.2 Input Selection Block

Figure 14-2 shows the configuration of the input selection block.

The input selection block selects a pin to be used by using the ADCCH2 through ADCCH0 flags. Only one

pin can be used for the A/D converter. When one of the P0D0/AD0 through P0D3/AD3, P1C2/AD4, and P1C3/

AD5 pins is selected, the other five pins are forcibly set in the input port mode.

The P0D0/AD0 through P0D3/AD3 pins can be connected to a pull-down resistor if so specified by the P0DPL0

through P0DPLD3 flags.

To use the P0D0/AD0 through P0D3/AD3 pins for the A/D converter, therefore,

disconnect their pull-down resistors to correctly detect an external input analog voltage.

Figure 14-3 shows the configuration of the A/D converter channel selection register.

Figure 14-2. Configuration of Input Selection Block

P1C3/AD5

P1C2/AD4

P0D3/AD3

P0D2/AD2

P0D1/AD1

P0D0/AD0

Selector

Each I/O port

ADCCH2

ADCCH1

ADCCH0

Compare block

VADCIN

UPD17708 Datasheet(PDF) 194 Page - NEC