can bus shield

Projects Networking, Protocols, and Devices
1

Hi,
I am working with can bus shield and following this structure
http://www.seeedstudio.com/wiki/CAN-BUS_Shield

but I used 2 arduino mega 2560 and use "send" code as in this topic
http://forum.arduino.cc/index.php?topic=127203.msg956663#msg956663
but the serial output printed "can init fail"

i tried to used the eleven board (it's looks like arduino Uno) and the sending output is fine
so what is the differences between mega 2560 and Uno?
how can i do this with 2 mega 2560 boards?
I also connect pin 50,51,52,53 to pin 10,11,12,13 as in FAQ in structure page

thank you

2

The CAN BUS shield is not compatible with the Mega2560 because the SPI signals are connected to pin 11, 12 and 13 and not to the ICSP header as suggested by Arduino.

You can make it work if you re-route the pins the following way:

Shield Arduino

10 10 (or 9 to 9 if you changed that switch)
11 50
12 51
13 52
2 2
5V 5V
GND GND

3

hi,
do u mean I have to connect these pins like this

I conneect like this and run the code, then

Enter setting mode fail
Can init fail!!
OK.
0
OK.
0
ERROR.
0
ERROR.
6
ERROR.
6
OK.
0
OK.
0
...

with mega 2560, can shield only has power led on
with uno board, can shield has 3 led on, power, Tx and Rx

4

I cannot access the URL you posted.

5

sorry!
you can check this link

6

That doesn't work because you still have the connections to the pins 11,12 and 13 of the Mega2560 (I guess you haven't cut them). Don't connect the shield directly but just connect the pins I mentioned.

7

I connect direct them as in picture and bend these 3 pins 11,12 and 13, so they was not connected direct to Mega board
then use 3 jumper to connect then with pin 50, 51 and 52
and it does not work

8

Excuse me, I had an error in my table, MISO is pin 12 on the UNO but pin 50 on the Mega2560 and MOSI is pin 11 on the UNO and pin 51 on the Mega2560. You have to swap these two pins from my table. I should always check these stuff and not write down from mind. pin 13 to 52 for SCKL is correct.

9

dont know why but I did that way but it still error

10

At the moment I don't see another reason for the failures. Do you have the possibility to attach a scope or logical analyzer to check the signals?

11

how about the pins table in this link
http://modelrail.otenko.com/arduino/arduino-controller-area-network-can

I tried and output looks better