3 prom reading procedure – NEC uPD78056Y User Manual

Page 558

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CHAPTER 26

µ

PD78P054, 78P058

Address Input

A0-A16

CE (Input)

OE (Input)

D0-D7

Hi-Z

Data Output

Hi-Z

26.4.3 PROM reading procedure

PROM contents can be read onto the external data bus (D0 to D7) using the following procedure.

(1) Fix the RESET pin low, and supply +5 V to the V

PP

pin. Unused pins are handled as shown in paragraph,

(2) “PROM programming mode” in section 1.5 or 2.5 Pin Configuration (Top View).

(2) Supply +5 V to the V

DD

and V

PP

pins.

(3) Input the address of data to be read to pins A0 through A16.

(4) Read mode is entered.

(5) Data is output to pins D0 through D7.

The timing for steps (2) through (5) above is shown in Figure 26-8.

Figure 26-8. PROM Read Timing

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