UPD78P4916 Datasheet, PDF (27/56 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLER

µPD78P4916
4.3 PROM Read Procedure
The contents of PROM can be read onto external data bus (D0-D7) as described below:
(1) Fix RESET pin to low and supply +5 V to VPP pin. Connect other unused pins as specified in “(2) PROM
Programming Mode” in section “Pin Configuration (Top View)."
(2) Supply +5 V to the VDD and VPP pins.
(3) Input the address of the data to be read to the A0-A16 pins.
(4) Enter the read mode (CE = L, OE = L).
(5) Output data to D0-D7 pins.
The above operation timing from (2) to (5) is shown in Figure 4-5.
Figure 4-5. PROM Read Timing
A0 - A16
Address input
CE (Input)
OE (Input)
Hi-Z
D0 - D7
Data output
Hi-Z
4.4 Screening One-time PROM Versions
The one-time PROM version (µPD78P4916GF-3BA) cannot be completely tested by NEC for shipment because
of its structure. For screening, it is recommended to verify PROM after storing the necessary data under the following
conditions:
Storage Temperature
125 ˚C
Storage Time
24 hours
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