4 IN 1 RF module integrates four RF chips( CC2500, NRF24L01, A7105, CYRF6936 ) in one single PCB board.
It supports more than 10 different protocols while working with MCU board, such as Frsky, Flysky, Hisky, Devo, DSM2, V2x2 and so on.
You can use arduino nano to DIY your own MCU board, it also can be used with walkera devo transmitter.

Description:

1. Arduino promini 5V/16Mhz(Protocols are using as witness the existing on board LED on B5 pin). It can be used also any setup with Atmega328P/16Mhz.
2. A7105 module(X7105-D03 PA/LNA module, V911,V939 harvested TX modules)
3. CC2500 PA/LNA module
4. Nrf24L01 PA/LNA module
5. Devo module(based on CYRF6936)
6. AMS1117 -5V and AMS1117-3.3V, LDO voltage regulator or any other regulators over 800mA.
7. Resistor 20K(between NRF_CE pin to Vcc)
8. Caps 22-47uF(3 pcs on ldo's)
9. Rotary dip switch 16 positions or DIP switch 4 positions this is required only in PPM mode.
Now in the serial mode with er9x/ersky9x/opentx there is no need to use dial switch anymore.

Pin function:
Number Name Property Description 1 VCC Power 3.3V Power supply 2 GND Power ground 3 PE1 input Switch for RF chips, See the truth table 4 PE2 input Switch for RF chips, See the truth table 5 CSN1 input A7105 chip select 6 CSN2 input CC2500 chip select 7 CSN3 input NRF24L01 chip select 8 CSN4 input CYRF6936 chip select 9 SCK input SPI clock signal 10 MOSI input SPI input for slave device 11 MISO output SPI output for slave device 12 CYRF_RST input CYRF6936 Reset 16 RFO in/out RF signal, connect to antenna others GND Power ground
Truth table:
status PE1 PE2 A7105 RF signal to antenna Low level Low level CC2500 RF signal to antenna Low level high level NRF24L01 RF signal to antenna high level Low level CYRF6936 RF signal to antenna high level high level
For more information, please visit the RCG forum:
http://www.rcgroups.com/forums/showthread.php?t=2165676

Example for MCU Board:

Package included:

1 x DIY 2.4G CC2500 NRF24L01 A7105 CYRF6936 Multi RF 4 IN 1 Wireless Module