Xiegu G90 MCU and DB9 reference

## Board revision: V2.0.7 GAI03 

## LCD Display: KD018QQTBN009-RT 

 Link to manufacturer: http://en.tft-tft.com/product/detail?id=19 

### uC pinouts and signals

 

FRONT PANEL UNIT
STM32F103RCT6 - LQFP64
Pin no	Pin name	Description
51	PC10	USART_3_Rx 3.5mm PC_RING
52	PC11	USART_3_Tx 3.5mm PC_TIP
42	PA9	USART_1_Tx to MAIN DB9_2
43	PA10	USART_1_Rx from MAIN DB9_3
MAIN UNIT
STM32F429ZGT6 - LQFP144
Pin no	Pin name	Description
96	PC6	USART_6_Tx to Front Panel DB9_3
97	PC7	USART_6_Rx from Front Panel DB9_2

DB9 connector between MAIN UNIT and FRONT PANEL

Pin	Description
1	9V after POWER ON from PWR Board LM2940-9.0 LDO
2	USART From PANEL to MAIN UNIT
3	USART From MAIN UNIT to PANEL
4	Vcc (13.8V) on stand by /POWER COMMAND/ 3V3 on POWER ON
5	GND

Xiegu G90 power supply section

 Here is the schematic for the power supply section on the PA Board of the Xiegu G90 transceiver.

The board is marked "G90-BASEBD-V2.0.7-GAI01" and contain:

-Power supply section with EMI filter, reverse voltage protection, electronic power switch, linear regulators for 9V (LM2940-9.0) and 5V (LM7805).

-Tx drivers

-Tx PARF

-Dir/Ref RF power bridge

-Band filters

-Antenna Matching Unit (ATU).

Here is the schematic for the power supply section (for high resolution click on image then right click and "save as"):

NOTE: There is an error in the diagram; will be corrected soon. The voltage divider R3/R4 is connected to the main V+ and not to the 9V rail.

Most probably, there is an error in the resistor values, the resistive divider most probably is connected to the ADC input of the main MCU for Battery voltage indicator.  Thanks Jake G1YFF for this pertinent observation!

You can download the schematic as pdf HERE.