µPD17P218

12

3.

WRITING/VERIFYING ONE-TIME PROM (PROGRAM MEMORY)

The program memory of the

µPD17P218 is a one-time PROM of 8192 x 16 bits. To write data to or verify this one-

time PROM, the pins shown in the following table are used. No address input pin is used, as the address is updated

by the clock input from the CLK pin.

Table 3-1 Pins Used to Write/Verify Program Memory

Pin Name

VPP

VDD

CLK

MD0-MD3

D0-D7

Function

Applies voltage when program memory is written/verified.

Apply +12.5 V to this pin.

Positive power supply.

Apply +6 V to write/verify program memory.

Input clock to update address when program memory is written/verified.

Program memory address is updated when four pulses are input to this pin.

Select operation mode when program memory is written/verified.

Input/output 8-bit data when program memory is written/verified.

3.1

OPERATION MODE FOR WRITING/VERIFICATION OF PROGRAM MEMORY

If +6 V is applied to the VDD and +12.5 V to the VPP pin after

µPD17P218 has been placed in the reset status for a

fixed time (VDD = 5V, RESET = 0V),

µPD17P218 enters program memory write/verify mode.

The MD0 to MD3 pins are used to set the operating modes listed in the following table.

Leave the pins not used for program memory writing/verification open or connect to GND through pull-down

resistors (470

Ω) (Refer to PIN CONFIGRATION (2) PROM programming mode).

Table 3-2 Operating Mode Specification

Operating Mode Specification

Remarks:

×: don‘t care (L or H)

MD0

MD1

MD2

MD3

HL

H

L

LH

H

H

LL

H

H

H

×

HH

VDD

+6 V

VPP

+12.5 V

Operating Mode

Program memory address 0 clear mode

Write mode

Verify mode

Program inhibit mode