Service Manual

15
MCU Control Section
The block diagram for the MCU control section is shown below. MCU works under the 7.3728MHz
clock frequency.
Channel SW
MB95F108AK
WPFV-GE1
U605
PTT
MON
BAT
A T 2 4 C 6 4
U609
APC/TUNE
PLL
1.vox
2.BUSY_DET
8.UART
7.W/N
6.DC/CTC
5.SAVE
4.T/R
3.BEEP/CALL
X601
9.BAT_DET
U610
Reset
IC
10.PLL_LD
7.3728M 晶体
Figure 9
The MCU control section is composed of MCU, EEPROM, RESET IC, keys, Channel Selector knob,
etc. Main functions realized by this circuit section are:
1. Control Signal:
Control of battery save mode
Control of high/low power switch
Control of band/narrow band switch
Control of Tx-Rx switch
Control of APC/TUNE output voltage
Control of Tx power supply and power supply of audio power amplifier
Control of squelch ON detect
2. Signal Detect