KakuteF4: Add BRD_ALT_CONFIG for serial RC_INPUT #26975
Conversation
On Kakute F4 V2.4 there are pads R3, T3 intended for rc input of ELRS, CRSF etc. This is not possible with default configuration. Therefore add it as alternative board config. Signed-off-by: Patrick Menschel <menschel.p@posteo.de>
by try and error method. Signed-off-by: Patrick Menschel <menschel.p@posteo.de>
Signed-off-by: Patrick Menschel <menschel.p@posteo.de>
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I have to admit, it does not work yet and I have contacted the manufacturer to ask if there are any specialties with USART3. At least it does seem to work out on betaflight. |
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Not working yet, I was trying to verify correct connections by flashing back to BetaFlight and found out that DFU flashing is broken in Ardupilot. |
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I have verified, that exactly the same connections to R3, T3, 5V, GND works for Betaflight. And I found a caveat in Kakute F4 V2.4, that basically Boot Button does NOT establish DFU mode when the ELRS receiver is connected this way. |
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I will revert and create new board file based on |
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I have a working setup on UART3 with CRSF. I had to change the POL property to 0 for the inverter. There is something fishy about the RC update rates and the not available telemetry from ArduCopter. I'll try the NODMA option next. |
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From what I learned by try&error. The Serial Options on Serial5 / Uart3 are not taken into account. The only thing that changes something is changing the POL() property in hwdef file. After that I get RC Input from the ELRS Receiver but the rates seem to be messed up and this ping failedshows that the TX part does not work as expected. Obviously the only telemetry I get is from the ELRS Receiver, nothing from ardupilot. I'll try flashing back to Betaflight and see if telemetry works. This is my current log.
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I just found an electrical issue on the tx cable from FC to ELRS receiver, seems to be a short to ground. Will investigate. |
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OK, electrical issue solved. On the Happymodel ES900RX, the Ground Plane apparently comes out of the board edge where they broke the pcb into separate receivers and soldering cables vertically into the groove seems to have bridged the RX PAD to GND. I now have working CRSF but the crucial thing was the POL(0) on the inverter. It does find nothing if the inverter is left with POL(1) setting. Please advise how to handle this.
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I have just verified, that BRD_ALT_CONFIG = 0 still works for SBUS with my latest patchset. I tested with a Turnigy Evolution + TGY-iA6C. I don't know why SBUS does not turn up in the log though.
Anyway, please advise on the next steps. |
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@Holybro Please add your thoughts on this. I mean Ardupilot does not use UART for SBUS in general, so what is the point in having the inverter. |
This is literally what the betaflight config does - no need to consult Holybro.
You are incorrect, ArduPilot can use a UART for SBUS just fine. |
OK, what are the configuration Parameters necessary? I can test it. |
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I realized this change is a stupid idea since USART2 has no DMA. Sorry for the noise. |
DO NOT MERGE
Hello,
I'd like to propose adding alternative board configuration for Holybro Kakute F4 to make the rc input pins available for bi-directional protocols like CRSF.
It does work on these pins in Betaflight. Reference commit in BetaFlight that upgraded the Kakute F4 board.
betaflight/betaflight#4427
It also is what Holybro suggests as wiring.
I used #13157 as a template.
From my experimentation, it does not work out but I ran out of ideas what the issue is.