HYT POWER446, Service Manual

Page: 17 / 61

POWER446 Service Manual
15
CPU Pins
Pin No. Port Name Pin Name I/O
Description
1 AVcc Vcc
I
A/D power supply pin; to connect with the
power supply.
2 AVR Vcc
I
A/D reference input pin; to connect with the power
supply.
3 PE3/INT13 PTT I
PTT key input pin (connected with external
pull-up resistor) (valid at low level)
.
4 PE2/INT12 A_KEY I
SK1 input pin (connected with external pull-up
resistor) (valid at low level)
5 PE1/INT11 EXT-PTT I
Earpiece PTT input pin (connected with
external pull-down resistor) (valid at high level)
6 PE0/INT10 B_KEY I
SK2 input pin (connected with external pull-up
resistor) (valid at low level)
7 P83 ENC3 I
8 P82 ENC2 I
9 P81 ENC1 I
10 P80 ENC0 I
Channel Selector knob input pin (connected
with external pull-up resistor)
11 P71/TI0 T/R O
For TX/RX switch control: High (RX)/Low(TX)
12 P70/TO0 Reserve O Reserved
13 MOD Programming I
During programming, this pin is used to
connect with VCC and a 47K resistor is
connected between the pin and the grounded
Vss; otherwise, only a 47K resistor is
connected between the pin and the grounded
Vss.
14 X0 OSC0
O
15 X1 OSC1
I
For 7.3728MHz main crystal oscillator
16 Vss GND /
For grounding (During programming, this pin is