16 x1 and x2, 17 xt1 and xt2, 18 vdd – NEC uPD78056Y User Manual
Page 86: 19 vss, 20 vpp (prom versions only), 21 ic (mask rom version only)
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CHAPTER 4 PIN FUNCTION (
µ
PD78054Y Subseries)
4.2.16 X1 and X2
Crystal resonator connect pins for main system clock oscillation. For external clock supply, input it to X1 and its
inverted signal to X2.
4.2.17 XT1 and XT2
Crystal resonator connect pins for subsystem clock oscillation.
For external clock supply, input it to XT1 and its inverted signal to XT2.
4.2.18 V
DD
Positive power supply pin
4.2.19 V
SS
Ground potential pin
4.2.20 V
PP
(PROM versions only)
High-voltage apply pin for PROM programming mode setting and program write/verify. Directly connect to V
SS
in the normal operating mode.
4.2.21 IC (Mask ROM version only)
The IC (Internally Connected) pin is provided to set the test mode to check the
µ
PD78054Y Subseries before
shipment. Directly connect the pin to the V
SS
with the shortest possible wire in the normal operating mode.
When a voltage difference is produced between the IC pin and V
SS
pin because the wiring between those two pins
is too long or an external noise is input to the IC pin, the user's program may not run normally.
Directly connect IC pins to V
SS
pins.
V
SS
IC
As short as possible