CHAPTER 2 PIN FUNCTIONS
31
(11) RESET (Reset) ... Input
The active-low reset input.
(12) ANO0, ANO1 ... Output
The D/A converter analog voltage output pins.
(13) AV
REF1
The A/D converter reference voltage input pin.
(14) AV
REF2
The D/A converter reference voltage input (+ side) pin.
(15) AV
REF3
The D/A converter reference voltage input (– side) pin.
(16) AV
DD
The A/D converter power supply pin. This should be made at the same potential as the V
DD
pin.
(17) AV
SS
The A/D converter GND pin. This should be made at the same potential as the V
SS
pin.
(18) V
DD0
Positive power supply pins of the ports. These pins should be made at the same potential as the V
DD1
.
(19) V
DD1
Positive power supply pins of the function blocks other than ports. These pins should be made at the same potential as
the V
DD0
.
(20) V
SS0
GND potential pins of the ports. These pins should be made at the same potential as the V
SS1
.
(21) V
SS1
GND potential pins of the function blocks other than ports. These pins should be made at the same potential as the V
SS0
.
(22) TEST
Pin used by NEC for IC testing. Must be directly connected to V
SS0
.
Caution
In the
μ
PD78233 and 78237, the TEST pin is the MODE pin and is fixed high. When changing over from
the
μ
PD78233, 78237, the circuitry can be modified so that this pin is directly connected to V
SS0
.
Any modification is needed if the
μ
PD78234, 78238 was used with switching between the on-chip ROM
mode and ROM-less mode performed by MODE pin switching (the TEST pin must be directly connected
to V
SS0
).
Modification examples:
Incorporate all programs in ROM.
Store all programs in external ROM.
Change the location address of a program previously held in external ROM, shift the address to avoid
overlapping internal ROM, and execute this program from the program internal ROM.