esp32 hangs on CAN.endPacket();

[creativtransfer]

I have no transceiver attached and when sending a packet, the ESP32 hangs upon executing CAN.endPacket();

Also when configured for loopback mode.

Which ESP32 Version do you use?

[stiebel]

I have the same problem. with no receiver CAN.endPacket() should return an error but hangs instead. Same problem when sending RTR - hangs instead of returning error. If not to fix I at least need a workaround. I work with a couple of WROOM32

[noiasca]

Same here. Without transceiver ESP32 hangs in the while ((readRegister(REG_SR) & 0x08) != 0x08) { and doesn't get beyond row 226

[noiasca]

to get an error and avoid hanging of the lib i found a workaround and added an errorhandling based on my returncodes.

extend the while loop in file ESP32JA1000.cpp row 219:

// wait for TX complete while ((readRegister(REG_SR) & 0x08) != 0x08) { // 0000‭1000‬ Transmission complete status. 0 = incomplete //Serial.print(F("D220 REG_SR:")); Serial.print(readRegister(REG_SR)); Serial.print(F(" REG_ECC:")); Serial.println(readRegister(REG_ECC)); if (readRegister(REG_ECC) == 0xd9) { // 217=‭11011001‬ modifyRegister(REG_CMR, 0x1f, 0x02); // error, abort return 0; } if (readRegister(REG_SR) == 0x30) { // e.g. if no transceiver is connected REG_SR=48 (‭0b00110000‬) ECC=0 modifyRegister(REG_CMR, 0x1f, 0x02); // error, abort Serial.print(F("D227 abort ")); Serial.println(readRegister(REG_SR)); return 0; } yield(); }

[NeliusNDL]

to get an error and avoid hanging of the lib i found a workaround and added an errorhandling based on my returncodes.

extend the while loop in file ESP32JA1000.cpp row 219:

// wait for TX complete while ((readRegister(REG_SR) & 0x08) != 0x08) { // 0000‭1000‬ Transmission complete status. 0 = incomplete //Serial.print(F("D220 REG_SR:")); Serial.print(readRegister(REG_SR)); Serial.print(F(" REG_ECC:")); Serial.println(readRegister(REG_ECC)); if (readRegister(REG_ECC) == 0xd9) { // 217=‭11011001‬ modifyRegister(REG_CMR, 0x1f, 0x02); // error, abort return 0; } if (readRegister(REG_SR) == 0x30) { // e.g. if no transceiver is connected REG_SR=48 (‭0b00110000‬) ECC=0 modifyRegister(REG_CMR, 0x1f, 0x02); // error, abort Serial.print(F("D227 abort ")); Serial.println(readRegister(REG_SR)); return 0; } yield(); }

Thanks for this. I'll give it a try as I have the same problem. Is this still the best way to do it? Any updates to the libraries? Any better CAN bus library?

[noiasca]

I don't see a change in the lib, so i guess this workaround still works.

[DNThomas]

I have a transceiver attached (SN65HVD230). When plugged into a vehicle CAN bus, the lib performs as expected. When unplugged from the vehicle , it still hangs at the CAN.endPacket(); even with the above workaround.

I ended up just putting a timeout in place instead and that seems to work.

[ghost]

I have the same error but Im not sure if the transceiver is connected. it should but I can't verify it.

[NeliusNDL]

look at this for a solution https://github.com/sandeepmistry/arduino-CAN/issues/60#issuecomment-786664485