X1 And X2; Av Ref; Vdd; Vss - NEC 78K0S/KA1+ User Manual

2.2.7 X1 and X2

These pins connect an oscillator to oscillate the X1 input clock.
X1 and X2 also function as the P121 and P122, respectively. For the setting method for pin functions, see
CHAPTER 17 OPTION BYTE.
Supply an external clock to X1.
Caution The P121/X1 and P122/X2 pins are pulled down during reset.
2.2.8 AV
REF
This pin inputs a reference voltage to the internal A/D converter. When the A/D converter is not used, connect this
pin to V .
DD
2.2.9 V
DD
This is the positive power supply pin.
2.2.10 V
SS
This is the ground pin.
In the 78K0S/KA1+, V
SS
to a stabilized GND (= 0 V).

2.3 Pin I/O Circuits and Connection of Unused Pins

Table 2-1 shows I/O circuit type of each pin and the connections of unused pins.
For the configuration of the I/O circuit of each type, refer to Figure 2-1.
Table 2-1. Types of Pin I/O Circuits and Connection of Unused Pins
Pin Name
P20/ANI0 to P23/ANI3
P30/TI000/INTP0
P31/TI010/TO00/INTP2
P34/RESET
P40
P41/INTP3
P42/TOH1
P43/TxD6/INTP1
P44/RxD6
P45
P121/X1
P122/X2
P123
P130
AV
REF
CHAPTER 2 PIN FUNCTIONS
functions alternately as the ground potential of the A/D converter. Be sure to connect V
I/O Circuit Type I/O
11 I/O
8-A
2 Input
8-A I/O
16-B
8-A
3-C Output
− Input
User's Manual U16898EJ3V0UD
Recommended Connection of Unused Pin
Input: Independently connect to AV
Output: Leave open.
Input: Independently connect to V
Output: Leave open.
Connect to V via a resistor.
DD
Input: Independently connect to V
Output: Leave open.
Input: Independently connect to V
Output: Leave open.
Input: Independently connect to V
Output: Leave open.
Leave open.
Directly connect to V .
DD
SS
or V via a resistor.
REF SS
or V via a resistor.
DD SS
or V via a resistor.
DD SS
via a resistor.
SS
or V via a resistor.
DD SS
25