µPD61P24

9

11. PIN FUNCTIONS

11.1

KI/O Pin (P0)

This is the 8-bit I/O pin for key-scan output. When the control register (P1) is set for the input port, the port can

be used as an 8-bit input pin. When the port is set for the input mode, all of these pins are pulled down to the VSS

level inside the LSI.

At reset (all cleared), the value of I/O mode and output latch becomes undefined.

Figure 11-1. KI/O Pin Organization

KI/O7

KI/O6

KI/O5

KI/O4

KI/O3

KI/O2

KI/O1

KI/O0

P0

P10

P00

(P )

Control register

1

11.2

KI/O Pull-Down Resistor Configuration

V DD

V SS

CMOS

N-ch

Pin

Pull-down resistor

Input signal

Output signal

Input/output selection

N-ch

P-ch

R

When KI/O is set to the input mode, pull-down resistor R is turned on.