Timeouts are not overflow-safe

Flole998 commented 2 years ago

Everytime this code checks a timeout a non-overflow approach was chosen. See https://arduino.stackexchange.com/questions/12587/how-can-i-handle-the-millis-rollover for further explanations.

For example:

  resptime = millis() + msturnaround;

  while (sdmSer.available() < FRAMESIZE) {
    if (resptime < millis()) {
      readErr = SDM_ERR_TIMEOUT;                                                //err debug (4)
      break;
    }
    yield();
  }

should be

  resptime = millis();

  while (sdmSer.available() < FRAMESIZE) {
    if (millis() - resptime > msturnaround) {
      readErr = SDM_ERR_TIMEOUT;                                                //err debug (4)
      break;
    }
    yield();
  }

Same for the SDM::flush function.

reaper7 commented 2 years ago

@Flole998 - you're right. I will be grateful if you can find time to prepare a PR tnx!

reaper7 commented 2 years ago

done https://github.com/reaper7/SDM_Energy_Meter/commit/5121587c68992cdedc5fbdea232f055f5f120709

reaper7 / SDM_Energy_Meter

Timeouts are not overflow-safe #63