Very easy canbus-signal tester.....

Projects Networking, Protocols, and Devices
1

Hello

Today i can send canbus from one canbus shield to another but I want the receiver to compare the received data with a master.

Why???
My project:
I will test some different canbus cables and thats because i want to send canbus for maybe 12Hours and then see if any of the package has been broken!

Any help???

/Peter

2

how much data are you planning to compare?
how is the master data stored? SD card?
would it be simpler to use a USB-Canbus dongle on a PC and compare with data stored on the PC?

3

Hello!
And thanks for answere!

I think it's enough with one data pack that repeats itself. And in the receiver, compare the package and have a counter that indicates if there is a diff.

I think its a very easy program but i didnt get the function...

I have use the code from seeed-studio at github.

4

what is the problem?
does the test fail after a time?
post your code?

5

Sorry, the program are on my computer on my work....

But i use the seeed-studio program send/receive.

The problem is to get the "canbusstring" into one string that i can compare with.
Now i get 8 small string.... ( buf)
How can i do to the 8 (BUF) to be only one!
Hope you get it!

#include <SPI.h>
#include "mcp_can.h"

// the cs pin of the version after v1.1 is default to D9
// v0.9b and v1.0 is default D10
const int SPI_CS_PIN = 9;

MCP_CAN CAN(SPI_CS_PIN); // Set CS pin

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

while (CAN_OK != CAN.begin(CAN_500KBPS)) // init can bus : baudrate = 500k
{
Serial.println("CAN BUS Shield init fail");
Serial.println(" Init CAN BUS Shield again");
delay(100);
}
Serial.println("CAN BUS Shield init ok!");
}

void loop()
{
unsigned char len = 0;
unsigned char buf[8];

if(CAN_MSGAVAIL == CAN.checkReceive()) // check if data coming
{
CAN.readMsgBuf(&len, buf); // read data, len: data length, buf: data buf

unsigned int canId = CAN.getCanId();

Serial.println("-----------------------------");
Serial.print("Get data from ID: ");
Serial.println(canId, HEX);

for(int i = 0; i<len; i++) // print the data
{
Serial.print(buf*, HEX);*

  • Serial.print("\t");*
  • }*
  • Serial.println();*
  • }*
    }
6

after the CAN.readMsgBuf(&len, buf); the incomming message is in buf[] and you can compare it with your test data using memcmp() function

7

Thanks very much!!!
I will test it!!!

8

Hello

Have it worked!
But unfortunately, it does not work with canid, somehow I do not get it to work to compare it with an int string.

I also test with " if (id == canId) " but whatever I choose, it does not work.

Do you think that CanId can be something other format??

If I wrote serial.print(myid) and serial.print(canId) its the same but nothing happend in the IF....

9

how many bits are you using to store canID?
if you are using extended ID (29 bits) try

        unsigned long int canId = CAN.getCanId();