Invalid calibrateImage parameters prevent initializing with 915MHz frequency on SX126x-based STM32WLx about radiolib HOT 2 CLOSED

Looks like someone else had encountered same issue.

Yes, this has been reported (as part of a rather long discussion) here: #1051 (specifically #1051 (reply in thread))

if both the begin and end image calibration parameters are odd, then calibration succeeds. Output from a quick test program I wrote is attached here:

That's interesting, thank you for investigating this! Unforuntately since the Semtech LoRa developer forum went down it's been rather tricky to discuss this with anyone. I think I will implement rounding to an odd number with a note/warning that this has not been confirmed by the manufacturer.

from radiolib.

Apologies - it appears this issue is fixed on master branch in 5d74177

Looks like someone else had encountered same issue.

Might still be worthwhile to update calibrateImageRejection formula in SX126x.cpp to round both parameters to an odd value, but since is no longer part of the default codepath for the basic beginner use cases, I could go either way.

int16_t SX126x::calibrateImageRejection(float freqMin, float freqMax) {
  // calculate the calibration coefficients and calibrate image
  uint8_t data[] = { (uint8_t)floor((freqMin - 1.0f) / 4.0f), (uint8_t)ceil((freqMax + 1.0f) / 4.0f) };
  data[0] = data[0]%2 ? data[0] : data[0]-1;
  data[1] = data[1]%2 ? data[1] : data[1]+1;
  return(this->calibrateImage(data));
}

from radiolib.