UPD78P324 Datasheet, PDF (19/80 Pages) NEC – 16-/8-Bit Single-Chip Microcomputers

µPD78P324, 78P324(A)
3.2 PROCEDURE FOR PROM WRITE
The procedure for writing into the PROM is as follows (see Figure 3-3).
(1) Fix to RESET = H; and AVDD = L. Other unused pins are processed as directed by the PIN CONFIGURATION.
(2) Supply +6.5 V to the VDD pin; and +12.5 V to the VPP pin. Enter the low level into the CE pin.
(3) Enter the initial address into A0-A16.
(4) Enter the Write data into D0-D7.
(5) Enter the 0.1 ms program pulse (active low) into the PGM pin.
(6) Verify mode. Check if the Write data has been written or not.
Enter the active low pulse into the OE pin and read the Write data from D0-D7.
• When written: Move to (8).
• When not able to write: Repeat (4) to (6). If it is not possible to write even when the repetition has been
made ten times, move to (7).
(7) Stop the Write operation as a defective device.
(8) Increment the address.
(9) Repeat (4) to (8) until the final address.
The timing of the above (2) to (7) steps is shown in Figure 3-2.
Figure 3-2. PROM Write/Verify Timing
Program
Program verify
A0-A16
Address input
Hi-Z
D0-D7
+ 12.5V
VPP
VDD
+ 6.5V
VDD
VDD
CE (input)
Data input
Hi-Z
Hi-Z
Data output
PGM (input)
OE (input)
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