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PROM VERSION
18.2 Usage precaution
18.2 Usage precaution
18.2.1 Precautions on all PROM versions
When programming to the built-in PROM, high voltage is required. Accordingly, be careful not to apply
excessive voltage to the microcomputer. Furthermore, be especially careful during power-on.
Noise gets in easily because the built-in PROM is wired directly from CNV
the wiring of CNV
SS
<In single-chip or memory expansion mode>
Connect CNV
(V
SS
If the wiring cannot be shortened, insert a resistor of about 5 kohms as close to CNV
possible. By way of this resistor, connect CNV
<In microprocessor mode>
Connect CNV
(V
SS
In single-chip and
memory expansion modes
M37751
CNV
The above processing is unnecessary for the BYTE (V
Figure 18.2.1 Wiring of CNV
18–10
(V
) pin is performed below. Figure 18.2.1 shows the wiring of CNV
PP
) pin to the microcomputer's V
PP
) pin to the microcomputer's V
PP
Shortest possible
distance
Approx. 5 kohms
(V
)
SS
PP
V
SS
(V
) pin
SS
PP
7751 Group User's Manual
pin in the shortest possible distance.
SS
(V
) pin to V
pin.
SS
PP
SS
pin in the shortest possible distance.
CC
In microprocessor mode
M37751
CNV
SS
) pin.
PP
(V
) pin. To prevent noise,
SS
PP
SS
(V
SS
V
CC
(V
)
PP
Shortest possible
distance
(V
) pin.
PP
) pin as
PP
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