µPD6125A, 6126A

10

input and output modes.

When “all clear” is input or on reset, input mode goes into effect, and the output latch value becomes undefined.

Figure 11-2. I/O Pin Organization

IN/OUT

IN/OUT

0 ······· Input mode

1 ······· Output mode

Note

Note

Note

11.4 I/O Pull-Down Resistor Organization

Input/output selection

CMOS

R

Nch

Pull-down resistor

I/O pull-down resistor switch

(Mask option)

P-ch

N-ch

Pin

Output signal

Input signal

The use of pull-down resistors for I/O can be selected by using the mask option.

When the pull-down resistor switch is turned on (1 is set) by the mask option, the pull-down resistor R is turned

on only in input mode.

Caution

When using the pins as key switches, turn on the pull-down resistor switch by the mask option.