Program memory read procedure – NEC PD75P308 User Manual

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PD75P308

3.3 PROGRAM MEMORY READ PROCEDURE

The contents of the program memory can be read in the following procedure.

(1) Ground the unused pins through pull-down resistors. The X1 pin must be low.

(2) Supply 5 V to the V

and V

pins.

(3) Wait for 10 microseconds.

(4) Set program memory address 0 clear mode.

(5) Supply 6 V to the V

pin and 12.5 V to the V

pin.

(6) Set program inhibit mode.

(7) Set verify mode. Data of each address is sequentially output each time a clock pulse is input to the

X1 pin four times.

(8) Set program inhibit mode.

(9) Set program memory address 0 clear mode.

(10) Change the voltages of V

and V

pins to 5 V.

(11) Turn off the power supply.

Steps (2) to (9) are illustrated below.

Data output

P40-P43

P50-P53

MD0

(P30)

MD1

(P31)

MD2

(P32)

MD3

(P33)