NEC PD78212, User Manual

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Chapter 17 Programming for The
µ
PD78214
17
Fig. 17-2 Write Operation Flowchart
17.3 PROCEDURE FOR READING FROM PROM
The contents of PROM can be read out to the external data bus (D0 to D7) by following the procedure below:
(1) Fix the RESET pin to the low level. Apply +12.5 V to pin NMI. Handle unused pins as described in Section 1.3.2 .
(2) Apply +5 V to the V
DD
and V
PP
pins.
(3) Input the address of the data to be read into the A0 to A14 pins.
(4) Set read mode.
(5) Output the data on the D0 to D7 pins.
Fig. 17-3 is the timing chart for steps (2) to (5).
Write failure (25th)
Write success
> Last address
Last address
Write failure (up to 24th)
(1)
(6)
(10)
(7)
(2)
(3)
(4)
(5)
(9)
<
Defective device
Start writing
Apply power supply voltage
Set an initial address
Verify mode
Last address
Write completes
Increment the address
Input a program pulse
Input write data
(8)
Additional write (3X ms pulse)
X: Number of times
writing is repeated