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CHAPTER 2 PIN FUNCTIONS
User’s Manual U15017EJ2V0UD
2.2.10 P100 to P107 (Port 10)
P100 to P107 constitute an 8-bit output port. These pins are also used as VFD controller/driver output pins.
The following operation modes can be specified in 1-bit units.
(1) Port mode
In this mode, P100 to P107 function as an 8-bit output port.
These pins are P-ch open-drain pins. Pull-down resistors can be specified for these pins in the mask ROM
versions in 1-bit units using a mask option. The
μ
PD78F4976A does not have pull-down resistors.
(2) Control mode
In this mode, P100 to P107 function as the output pins of the VFD controller/driver (FIP40 to FIP47).
2.2.11 FIP0 to FIP15
These are the output pins of the VFD controller/driver.
2.2.12 V
LOAD
This pin connects a pull-down resistor to the VFD controller/driver.
2.2.13 AV
DD
This pin supplies an analog voltage to the A/D converter.
Always keep this pin at the same potential as the V
DD1
pin even when the A/D converter is not used.
2.2.14 AV
SS
This is the ground pin of the A/D converter.
When the A/D converter is used (ADCS = 1), use the AV
DD
pin with the same potential as V
DD1
.
When the A/D converter is not used (ADCS = 0), the AV
DD
pin can be used with the same potential as V
SS1
.
2.2.15 RESET
This pin inputs an active-low system reset signal.
2.2.16 X1 and X2
These pins connect a crystal resonator for main system clock oscillation.
To supply an external clock, input it to X1, and input a signal reverse to that input to X1, to X2.
2.2.17 V
DD0
to V
DD2
V
DD0
supplies a positive voltage to the ports.
V
DD1
supplies a positive voltage to the internal function blocks other than the ports, analog block, and VFD controller/
driver.
V
DD2
supplies a positive voltage to the VFD controller/driver.
2.2.18 V
SS0
and V
SS1
V
SS0
is the ground pin for the ports.
V
SS1
is the ground pin for the internal function blocks other than the ports and analog block.
2.2.19 V
PP
(
μ
PD78F4976A only)
A high voltage is applied to this pin when the flash memory programming mode is used and when a program is
written or verified.
Directly connect this pin to V
SS1
in the normal operation mode.