OpenGround – Part 9 – CC2500 & some UI work

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By | September 27, 2016

This is the ninth post of my series documenting the development of a custom firmware for the FS-i6s transmitter. In my previous post we mapped the gpios for the buttons. This time it is not a real howto/tutorial but rather a short status overview.


I did some cleaning up of the code base and the Makefiles. I also added a stylechecker that takes care of reminding me how to properly format my code. The code can be found in the addingfrsky branch.

CC2500 module

I successfully removed the Flysky transceiver and soldered the cc2500 module to the mainboard.

Flysky FS-i6s custom firmware - soldered cc2500 and debug connections

For a short test i ported the OpenSky receiver code to the TX, this way i can bind the FS-i6s to my Turnigy 9x and receive data from it. It works, the cc2500 module communication works and i can sucessfully send and receive packets! yay!

Flysky FS-i6s custom firmware - Frsky bind test

Next on this front: Writing the FrSky tx code.


I also worked a bit on the user interface. I wrote a small slider demo screen for debugging and setup purposes. This is not yet calibrated data, it shows the raw analog data from the sticks.

FlySky FS-i6s custom firmware - ADC test

Above the stick data you can see my ideas about the RSSI (rx+tx) and the battery visualization. Stay tuned for more 😉

2 thoughts on “OpenGround – Part 9 – CC2500 & some UI work

    1. fishpepper Post author

      yes. the stock rf module is not compatible.


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