Mcu Control, Signal Processing And Audio Power Amplification; Mcu Control Circuit; Block Diagram Of Mcu Control Circuit - HYT TC-580 Service Manual

The newly generated signal at Q501 is processed by the crystal filter (Z1, Z2 or XF501) to generate the
first IF signal (21.7MHz). After amplified by Q505, this IF signal enters the IF demodulator U201, where
it will be mixed with the second local oscillator signal to generate the second IF signal (450KHz). Then
U201 demodulates this second IF signal and outputs an audio signal which will be sent to AK2347.

3. MCU Control, Signal Processing and Audio Power Amplification

Circuit diagram of this section is shown as below:
TTS_DET
CTC/DCS_DET
DTMF_DET
DTMF/TTS
CTC/DCS
VRCR
APA_EN

1) MCU Control Circuit

MCU control circuit is composed of MCU, EEPROM, keys and etc. This section has the
following functions: to initialize data of the radio and save data to EEPROM; to check the
battery voltage and signals from external keys, LD and VOX-DET, and make responses; to
transmit required data to PLL; to switch and control RX/TX status based on the input PTT
signal; to switch the squelch circuit on or off based on the input signaling decode signal
and squelch level signal; to control circuits of high/low power switch, audio power
amplification, VCO power supply, RX power supply and TX power supply; (for
programming) to communicate with PC via RXD/TXD, and transmit data to or receive data
from PC.
ALARM
PTT
KEY PAD
SK1
SK2 4*4
TTS_IN
CTC_IN
DTMF_IN
DTMF/TTS_OUT
CTC/DCS_OUT
AK2347
Figure 1.5

Block Diagram of MCU Control Circuit

LCD
E2PROM
CSTN
U611
CPU
STM32F100
9.8304M
VDD
R2
R
C2
C
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TC-580 Service Manual
BEEP
PLL_CLK
PLL_DATA
PLL_EN
LED_GREEN
LED_GREEN
LED_RED
LED RED
APC/TU
APC/TU
SAVE
SAVE
W/N
W/N
TX/RX
TX/RX
T/R
T/R
RSSI
RSSI
N-DET
Noise Detect
VOX_DET
VOX
TXD
RXD
POWER_CTRL