Going back to what worked on the Champ, a RB10, only problem, it is only 8 channels and I need 11. The critical channels are already mapped to channels 1 through 8 since those channels on the RB30+ report servo amps so just plug in channels 1 through 8 into the RB 10 and those are set, still need three more channels for the choke, starter, and nosewheel. Consider using a second RB 10 for the additional channels and had the firmware to change 1-8 to 9-16 however I couldn't get the firmware to load. Found the GitHub site that had the same firmware and it did not work as well. Considered using an old FrSky SBUS converter however my SBUS channel changer broke a few years ago and they are no longer available.
Ended up making a SBUS converter using a XAIO PR2040 board.. The XAIO PR2040 runs at 133mz while the older Arduino's run at 16mz. The code reads the SBUS data stream, 16 channels and the failsafe info. For normal servo limits the SBUS stream data is a number between 172 to 1811 which represents the servo position between 988 and 2012 us.. The number read for each channel is then mapped to the 988-2012 us range for normal servo movement. The code includes two failsafe settings, the first being a failsafe from the receiver, I have this set so the choke remains open, ignition on, and nosewheel centered. The second failsafe is the broken signal wire scenario, if the SBUS data stream is lost the servos go to the set failsafe position. The RB30 works in the same manner as the failsafe settings are coded into the device and do not rely on settings from the transmitter. If the power or ground is lost like everything else it just stops working. The board runs at 5 volts so included are a 5 volt linear regulator with filtering capacitors and a simple SBUS inverter circuit since FrSky uses inverted SBUS. Of course Google AI did most of the heavy lifting and my duties were mostly building, testing, and report back, then repeat. Took 6 to 8 hours over a two day period to arrive at the final design. In the photo below channels 14, 15 and 16 signal outputs are on the white header pin, servo power is a separate feed. The filtering cap's are as big as the control board!
Just might fly this bird next week.
