Failing to recieive

[arbrog]

Using an Arduino Mega 2560 with a FrySky R-XSR. I am using the SBUS_example.ino (as a base) on Serial2 (Pin 17 RX) and verified the program starts and the main loop runs but I never get inside the if

if(x8r.read(&channels[0], &failSafe, &lostFrame)){

    Serial.print("working");
  }

I put some return statements to shortcircuit SBUS read and it looks like the if (parse()) { on line 66 of SBUS.cpp is returning false. I used an oscilloscope to verify that my inverting circuit is working so I'm not sure why the packet isn't coming through correctly.

#include "SBUS.h"

// a SBUS object, which is on hardware
// serial port 1
SBUS x8r(Serial2);

// channel, fail safe, and lost frames data
uint16_t channels[16];
bool failSafe;
bool lostFrame;

void setup() {
  // begin the SBUS communication
  x8r.begin();
  Serial.begin(115200);
  Serial.println("start");

}

void loop() {

  // look for a good SBUS packet from the receiver
  Serial.println("polling: ");
  if(x8r.read(&channels[0], &failSafe, &lostFrame)){

    Serial.print("working");
  }

}

[arbrog]

so further debugging, in parse() I never get into while (_bus->available() > 0) { on line 299 so there are never bytes available to read?

if ((_curByte == _sbusHeader) && ((_prevByte == _sbusFooter) || ((_prevByte & _sbus2Mask) == _sbus2Footer))) { this if on line 305 never is true so the _parserState never increments

[swampd32618]

Did you ever resolve this issue? I'm experiencing the same problem and it's incredibly frustrating!

[arbrog]

I did not, but I also haven't worked on the project this was for since due to COVID

[nk-le]

I tried printing all values received from UART Buffer and they were wrong (in comparision to another app I used such as Logic Analyzer or Hterm). I guessed there might be something wrong with the the baudrate or format during the serial initialization so I modified the "begin()" of SBUS by just using "_bus->begin(_sbusBaud);" and it worked.

[circuitBurn]

Any update from anyone? Trying to get an R8 PRO receiver working, running into the same issue and @khanhln2907's suggestion didn't change anything for me.

[flybrianfly]

If anyone is able to get to the bottom of this, please re-open the issue with the specific steps taken, the microcontroller tested, and the necessary code changes relative to the most recent code. Thanks!