ESP32-EVB CAN return 0 with no receiver

[MeisterQ]

Hi,

im using the EVB Board to translate serial data from a Batterymanagement System to CAN for an Batteryinverter.

After i managed to fix this issue https://www.olimex.com/forum/index.php?topic=8919.0, get some more problems.

The batteryinverter is shut off at the moment because there is to much snow and my PV system is not producing any power.

The inverter is connected physically, but its complete shut off, so no receiver is connected.

But on my serial monitor, i get the message, that my can messages are sent successfully.

My CAN Code is looking like this:

Code Select Expand

void canConfig()
{
  CAN_cfg.speed = CAN_SPEED_500KBPS;
  CAN_cfg.tx_pin_id = GPIO_NUM_5;
  CAN_cfg.rx_pin_id = GPIO_NUM_35;
  CAN_cfg.rx_queue = xQueueCreate(rx_queue_size, sizeof(CAN_frame_t));
  ESP32Can.CANInit();

}


void can()
{
  unsigned long currentMillisCAN = millis();
  if ((currentMillisCAN  - previousMillisCAN  >= intervalCAN ))
  {
    previousMillisCAN  = currentMillisCAN ;

    sohLow =  soh & 0xff; // Nur die unteren 8 Bit
    sohHigh = soh >> 8; // um 8 Bit nach rechts schieben

    socLow =  soc & 0xff; // Nur die unteren 8 Bit
    socHigh = soc >> 8; // um 8 Bit nach rechts schieben

    chgVltLow =  chgVlt & 0xff; // Nur die unteren 8 Bit
    chgVltHigh = chgVlt >> 8; // um 8 Bit nach rechts schieben

    chgCurLow =  chgCur & 0xff; // Nur die unteren 8 Bit
    chgCurHigh = chgCur >> 8; // um 8 Bit nach rechts schieben

    disCurLow =  disCur & 0xff; // Nur die unteren 8 Bit
    disCurHigh = disCur >> 8; // um 8 Bit nach rechts schieben

    disVltLow =  disVlt & 0xff; // Nur die unteren 8 Bit
    disVltHigh = disVlt >> 8; // um 8 Bit nach rechts schieben

    data351[0] = chgVltLow;
    data351[1] = chgVltHigh;
    data351[2] = chgCurLow;
    data351[3] = chgCurHigh;
    data351[4] = disCurLow;
    data351[5] = disCurHigh;
    data351[6] = disVltLow;
    data351[7] = disVltHigh;

    data355[0] = socLow;
    data355[1] = socHigh;
    data355[2] = sohLow;
    data355[3] = sohHigh;

    ESP32Can.CANInit();
    CAN_frame_t tx_frame;
    tx_frame.FIR.B.FF = CAN_frame_std;

    if (canID == 0)
    {
      Serial.println("Sending package 351: ");
      tx_frame.MsgID = 0x351;
      tx_frame.FIR.B.DLC = 8;
      tx_frame.data.u8[0] = chgVltLow;
      tx_frame.data.u8[1] = chgVltHigh;
      tx_frame.data.u8[2] = chgCurLow;
      tx_frame.data.u8[3] = chgCurHigh;
      tx_frame.data.u8[4] = disCurLow;
      tx_frame.data.u8[5] = disCurHigh;
      tx_frame.data.u8[6] = disVltLow;
      tx_frame.data.u8[7] = disVltHigh;
      int sent351 = ESP32Can.CANWriteFrame(&tx_frame);

      if (sent351 == 0)
      {
        Serial.println("Package 351 sent successfully");
        client.publish(STATE_DEBUG_TOPIC, "Package 351 sent successfully");
      }
      else
      {
        Serial.println("Failed to send");
        client.publish(STATE_DEBUG_TOPIC, "Failed to CAN");
      }
      canID = 1;
    }
    else if (canID == 1)
    {
      Serial.println("Sending package 355: ");
      tx_frame.MsgID = 0x355;
      tx_frame.FIR.B.DLC = 8;
      tx_frame.data.u8[0] = socLow;
      tx_frame.data.u8[1] = socHigh;
      tx_frame.data.u8[2] = sohLow;
      tx_frame.data.u8[3] = sohHigh;
      int sent355 = ESP32Can.CANWriteFrame(&tx_frame);
      if (sent355 == 0)
      {
        Serial.println("Package 355 sent successfully");
        client.publish(STATE_DEBUG_TOPIC, "Package 355 sent successfully");
      }
      else
      {
        Serial.println("Failed to send");
        client.publish(STATE_DEBUG_TOPIC, "Failed to CAN");
      }
      canID = 0;
    }
    ESP32Can.CANStop();
  }
}


Class ESP32Can.CANWriteFrame returns 0 when successfully sent according to CAN.c here https://github.com/miwagner/ESP32-Arduino-CAN/blob/master/src/CAN.c

Code Select Expand

int CAN_write_frame(const CAN_frame_t *p_frame) {
if (sem_tx_complete == NULL) {
return -1;
}

// Write the frame to the controller
CAN_write_frame_phy(p_frame);

// wait for the frame tx to complete
xSemaphoreTake(sem_tx_complete, portMAX_DELAY);

return 0;
}

My function always returns 0, even there is no receiver connected.

When i switch on my inverter, it still says sent successfully, but the inverter is not receiving any data.

If i powercycle the EVB Board, the can connection to the batteryinverter is ok.

Thats why i tried to use ESP32Can.CANStop(); and ESP32Can.CANInit(); in cyclic program.

My EVB Rev is I.

Thank you in advance