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22.2.2 PROM write procedure
PROM contents can be written using the following procedure and high-speed writing is enabled.
(1) Fix the RESET pin low, and supply +5 V to the V
Configuration, (Top View), (2) PROM programming mode.
(2) Supply +6 V to the V
(3) Supply the initial address.
(4) Supply the written data.
(5) Supply the 1 ms program pulse (active low) to the CE pin.
(6) Verify mode. If written, proceed to step (8). If not written, repeat steps (4) through (6). If you repeat 25 times
and it can't be written, proceed to (7).
(7) Stop the write operation as a defective device.
(8) Supply write data and repeat times from (4) through (6) × 3 ms program pulse (additional write).
(9) Increment the address.
(10) Repeat steps (4) through (9) to the last address.
The timing for steps (2) through (8) above is shown Figure 22-2.
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A0 to A14
D0 to D7
+12.5 V
V
PP
V
DD
+6 V
V
DD
V
DD
CE (Input)
OE (Input)
498
CHAPTER 22 µ PD78P014, 78P014Y
pin and +12.5 V to the V
DD
Figure 22-2. PROM Write/Verify Timing
X-times Repeat
Write
Hi-Z
Data Input
pin. Unused pins are handled as shown in 1.5 or 2.5 Pin
PP
pin.
PP
Verify
Address Input
Hi-Z
Hi-Z
Data Output
Additional Write
Hi-Z
Data Input
3Xms
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