can communication between esp32 and arduino not working

[StijnVandendriessche1]

Hi

I am trying to make an ESP32 (running arduino) communicate with an arduino uno. Both have an MCP2515 board wired up as the following picture shows.

To enable the can communication via the board I am using the arduino-mcp2515 library. I uploaded the send example to the arduino uno, and the receive example to the ESP32 (changing the chip select to 5 wich is the standard chip select for the SPI bus on the ESP32), yet it is not working.

Does anyone know what I might be doing wrong?

Sending code on the Arduino Uno `#include

include

struct can_frame canMsg1; struct can_frame canMsg2; struct can_frame canMsg3; MCP2515 mcp2515(10);

void setup() { canMsg1.can_id = 0x0F6; canMsg1.can_dlc = 8; canMsg1.data[0] = 0x8E; canMsg1.data[1] = 0x87; canMsg1.data[2] = 0x32; canMsg1.data[3] = 0xFA; canMsg1.data[4] = 0x26; canMsg1.data[5] = 0x8E; canMsg1.data[6] = 0xBE; canMsg1.data[7] = 0x86;

canMsg2.can_id = 0x036; canMsg2.can_dlc = 8; canMsg2.data[0] = 0x0E; canMsg2.data[1] = 0x00; canMsg2.data[2] = 0x00; canMsg2.data[3] = 0x08; canMsg2.data[4] = 0x01; canMsg2.data[5] = 0x00; canMsg2.data[6] = 0x00; canMsg2.data[7] = 0xA0;

while (!Serial); Serial.begin(115200);

mcp2515.reset(); mcp2515.setBitrate(CAN_125KBPS); mcp2515.setNormalMode();

Serial.println("Example: Write to CAN"); }

void loop() { mcp2515.sendMessage(&canMsg1); Serial.print("sent "); Serial.print(canMsg1.can_id, HEX); Serial.println(); delay(5000); mcp2515.sendMessage(&canMsg2); Serial.print("sent "); Serial.print(canMsg2.can_id, HEX); Serial.println(); delay(5000); }`

Receiving code on the ESP32 `#include

include

struct can_frame canMsg; MCP2515 mcp2515(5);

void setup() { Serial.begin(115200);

mcp2515.reset(); mcp2515.setBitrate(CAN_125KBPS); mcp2515.setNormalMode();

Serial.println("------- CAN Read ----------"); Serial.println("ID DLC DATA"); }

void loop() { if (mcp2515.readMessage(&canMsg) == MCP2515::ERROR_OK) { Serial.print("CAN ID: "); Serial.println(canMsg.can_id); Serial.print("data: "); for (int i = 0; i<canMsg.can_dlc; i++) { // print the data Serial.print(canMsg.data[i],HEX); Serial.print(" "); } Serial.println();
} }`

Thanks in advance!

[dakhnod]

do you have both can modules terminated? There is a special jumper on the can boards for that. That's what helped in my case.

[StijnVandendriessche1]

Hi @dakhnod, thank's for your response. My project has already ended, but I do remember both of the boards being terminated by the on-board resistor. However, I do not remember what solved the problem. Good to hear that you got it working!