Can BUS Shield on Arduino Leonardo - Can't init CAN

Question

I'm hoping to get some help with this as I am unable to get the CAN to Initialize.

I have the sparkfun Can-Bus shield: https://www.sparkfun.com/products/13262

and an Arduino Leonardo board.

I'm using the following code to try to connect my 2008 Audi S6 to the Arduino board:

#include <Canbus.h>
#include <defaults.h>
#include <global.h>
#include <mcp2515.h>
#include <mcp2515_defs.h>
#include <Canbus.h>
char UserInput;
int data;
char buffer[456]; //Data will be temporarily stored to this buffer before being written to the file
//********************************Setup Loop*********************************//
void setup(){
Serial.begin(9600);
while(!Serial);
Serial.println("CAN-Bus Demo");
if(Canbus.init(CANSPEED_500)) /* Initialise MCP2515 CAN controller at the specified speed */
 {
Serial.println("CAN Init ok");
 } else
 {
 Serial.println("Can't init CAN");
 } 
 delay(1000); 
Serial.println("Please choose a menu option.");
Serial.println("1.Speed");
Serial.println("2.RPM");
Serial.println("3.Throttle");
Serial.println("4.Coolant Temperature");
Serial.println("5.O2 Voltage");
Serial.println("6.MAF Sensor");
}
//********************************Main Loop*********************************//
void loop(){
while(Serial.available()){
 UserInput = Serial.read();
if (UserInput=='1'){
 data=Canbus.ecu_req(VEHICLE_SPEED, buffer);
 Serial.print("Vehicle Speed: ");
 Serial.print(data);
 Serial.println(" km/hr ");
 delay(1000);
}
else if (UserInput=='2'){
 data= Canbus.ecu_req(ENGINE_RPM, buffer);
 Serial.print("Engine RPM: ");
 Serial.print(data);
 Serial.println(" rpm ");
 delay(1000);
}
else if (UserInput=='3'){
 data= Canbus.ecu_req(THROTTLE, buffer);
 Serial.print("Throttle: ");
 Serial.print(data);
 Serial.println(" %% ");
 delay(1000);
}
else if (UserInput=='4'){
 data =Canbus.ecu_req(ENGINE_COOLANT_TEMP, buffer);
 Serial.print("Engine Coolant Temp: ");
 Serial.print(data);
 Serial.println(" degC");
 delay(1000);
}
else if (UserInput=='5'){
 data=Canbus.ecu_req(O2_VOLTAGE, buffer);
 Serial.print("O2 Voltage: ");
 Serial.print(data);
 Serial.println(" V");
 delay(1000);
}
else if (UserInput=='6'){
 data=Canbus.ecu_req(MAF_SENSOR, buffer);
 Serial.print("MAF Sensor: ");
 Serial.print(data);
 Serial.println(" g/s");
 delay(1000);
}
else
{
 Serial.println(UserInput);
 Serial.println("Not a valid input.");
 Serial.println("Please enter a valid option.");
}
}
}

Overall, I just can't get the CAN to initialize. I've looked online and just can't seem to find a solid solution. I've tried other libraries as well to no avail.

Please assist!

• gre_gor: Leonardo has SPI pins on the ICSP header. Your shield expects SPI pins on pins 11,12 and 13. Maybe this will help: seeedstudio.com/wiki/…
• calcazar: I got that far; The strange part is that even if I bring the SPI pins to pins 11,12, and 13 it still doesn't work.. are there more pins I need bring over?

Answer 1

Had this problem myself. Found this fixed it

Change the following line...

_delay_us(10);

To...

_delay_us(50);

In the MCP2515.c file in the library

Answer 2

Increasing that delay in the MCP2515.c file also fixed this issue for me. I am running the sparkfun Can-Bus shield on an Arduino pro-mini, and here is my serial monitor output before the change, and after:

12:56:38.580 -> CAN Read - Testing receival of CAN Bus message 12:56:39.556 -> Can't init CAN 13:01:40.992 -> CAN Read - Testing receival of CAN Bus message 13:01:42.016 -> CAN Init ok