FrSky CPPM firmware update with Arduino
In this article I will describe, how to update the FrSky D8R-II Plus or D4R-II receiver with 27ms CPPM firmware. By using CPPM signal you only need one wire for all channels and not separate wires for every channel.
You can buy the FrSky Update Cable or you can use your Arduino board. You can use every Arduino, that has an integrated FTDI chip. I have one Arduino Uno, but my revision of the board doesn’t have a FTDI chip. So I decided to use my MultiWii MegaPirate AIO flight controller.
First you need to download the CPPM firmware.
This firmware for the D8R-II Plus is actually for the FrSky D8R-XP receiver, but it works fine. Please keep in mind, that it is officially not supported for the D8R-II Plus and I am not responsible for any damages on your hardware. Download the official FTDI Prog. – EEPROM Programming Utility and install it on your computer.
There is a jumper on the side of your receiver. Take it out and place the jumper on the signal pins for channel 7 and 8, so these are bridged. This will put the receiver into update mode.
Then connect the TX, RX and GND pins from your Arduino board to the TX, RX and GND pins on the side of your D8R-II Plus receiver. Important: Do not reverse the TX and RX as usual. Connect TX to TX and RX to RX. To power your receiver: you can use a 5V battery or connect it as usual to the flight controller.
For the update process we only need the use of the FTDI chip, so we will suppress the Atmega chip by a constant press on the reset button. After the reset button is pressed, connect your board to the USB port of your computer. It could possibly install some drivers, so give it some time. Keep pressing the reset button 🙂
Open the FTDI Prog. Scan for FTDI Devices. Then invert the TX and RX as shown on the screenshots below and click on the flash icon. In the new opened window click “Program”. (Tipp: Remember to undone this procedure after you have flashed your receiver)
Keep pressing the reset button 🙂 Now go to the folder, where you downloaded the firmware file from the FrSky website, extract it and start the .exe file.
Choose the right COM port in the dropdown menu. Select the firmware file from the same folder by clicking on “File”. If everything is fine, you should see the UID number in the bottom of window. If so, just click “Download” to upload the firmware.
Now you have a working CPPM FrSky receiver. To use your receiver in CPPM mode, place the jumper on signal pins CH3 and CH4, so these are bridged. The CPPM signal will be on CH1 pin. If you have any question just leave me a comment.