Electronics America 4-Bit Single-Chip Microcomputer User's Manual

CHAPTER 2. PIN FUNCTIONS

The

PD75402A operates by the pin functions in the normal operating mode.

For the

PD75P402’s pin functions, the 2 modes of the normal operating mode (

PD75402A mode) and the PROM

mode are available.

The operating mode switches according to the V

PP pin level as shown in the table below.

VPP Operating Mode

Low level (GND potential) Normal operating mode

High level (+5 V) PROM read mode

High level (+12.5 V) PROM write/verify mode

PROM mode