NEC PD78058FY(A) - Manual (Page 90)

90
CHAPTER 4 PIN FUNCTION (
µ
PD78058FY SUBSERIES)
V
SS
IC
As short as possible
4.2.21 IC (Mask ROM version only)
The IC (Internally Connected) pin is provided to set the test mode to check the
µ
PD78058FY Subseries at delivery.
Connect it directly 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.
Connect IC pins to V
SS
pins directly.