NEC PD750008 - Manual (Page 37)

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CHAPTER 2 PIN FUNCTIONS
2.2.18 IC (for the µPD750004, µPD750006, and µPD750008 only)
The internally connected (IC) pin is used to set the µPD750008 to test mode for inspection prior to shipping.
In normal operation, connect the IC pin to the V
DD
pin, keeping the writing as short as possible.
When the wiring between the IC pin and the V
DD
pin is too long, or noise is generated on the IC pin, a potential
difference may occur between the IC pin and the V
DD
pin. This may cause your program to malfunction.
• Connect the IC pin to the V
DD
pin, keeping the wiring as short as possible.
2.2.19 V
PP
(for the µPD75P0016 only)
This is a program voltage input pin for program memory (PROM) write/verify operation.
For normal use, connect this pin to V
DD
, keeping the wiring as short as possible (shown above).
+12.5 V is applied for PROM write/verify operation.
2.2.20 MD0-MD3 (for the µPD75P0016 only): I/O Pins Used Also for Port 3
MD0 to MD3 select a mode for program memory (PROM) write/verify operation.
V DD
V
DD
IC (V
PP
)
Keep the wiring
as short as possible