Arduino CAN Shield Help

General discussion about interfacing with the CAN bus
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cavemaneca
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Arduino CAN Shield Help

Post by cavemaneca » 2015 Jan 29 21:41

So, I wanted to mess around a bit with the stock Radio on my 2007 Dodge Caliber, but in order to "Bench Power" the radio I needed to emulate the CAN BUS. I have a few different Arduinos, so I ordered the following shield:

http://www.elecfreaks.com/store/canbus- ... p-746.html

One of the first issues I've run into, I can't find the baudrate I need to communicate with ANYWHERE. People just say things like "Slow" and "Fast" but that means nothing to me if it doesn't translate to a number. I'd like to know if someone can kindly explain what rate I need. The default library for this device has settings for 5,10,20,40,50,80,100,125,200,250,500 kbps.

With that I've just been testing different values, but I'm getting nothing.

As for what I'm sending, here's a small sample:

Code: Select all

unsigned char buffer[] = {0xFE, 0x16, 0x3f, 0xff, 0xff, 0xff, 0xff, 0xff};

CAN.sendMsgBuf(0x416 , 0, 8, buffer);
Am I headed in the right direction? Any hints as to what I'm doing wrong?

nr0x
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Re: Arduino CAN Shield Help

Post by nr0x » 2015 Jan 30 18:23

Well, from taking a brief look around but didnt find much on the protocols for your car, so I will tell you what I know about mine.
My 14 wrangler has multiple busses. the Can C bus (The big one) runs at 500 with 29bit id. But the Interior Bus (what MY stereo is on) is a 125 but with 11 bit id.

So my first question is this...does your vehicle have more than one bus, and if so, which bus is the stereo on?

Now I got my car from a small town dealer, and I just walked in to their service counter and asked them to print me the schematic for the data buss out of the service manual. That showed me the wire color code for the different busses and what they were called. it also shows which connector and pin you can find that wire on. Since I can't see through your eyes, that is the best "next step" I can give you.

Keep hacking!

cavemaneca
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Re: Arduino CAN Shield Help

Post by cavemaneca » 2015 Jan 30 23:13

nr0x wrote:Well, from taking a brief look around but didnt find much on the protocols for your car, so I will tell you what I know about mine.
My 14 wrangler has multiple busses. the Can C bus (The big one) runs at 500 with 29bit id. But the Interior Bus (what MY stereo is on) is a 125 but with 11 bit id.

So my first question is this...does your vehicle have more than one bus, and if so, which bus is the stereo on?

Now I got my car from a small town dealer, and I just walked in to their service counter and asked them to print me the schematic for the data buss out of the service manual. That showed me the wire color code for the different busses and what they were called. it also shows which connector and pin you can find that wire on. Since I can't see through your eyes, that is the best "next step" I can give you.

Keep hacking!
From what I understand, the Caliber has 3 Bus's, with the radio being on CAN-B with other interior things. I've got a wiring diagram for the C1 plug for my radio so I know the correct places to wire it up.

rtgree01
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Re: Arduino CAN Shield Help

Post by rtgree01 » 2015 Jan 31 14:28

My 2007 Dodge Charger has 2 buses.... the radio bus has a baud rate of 83.3k... I know that the 2008 models switched to the 125k speed. let us know if anything works

cavemaneca
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Re: Arduino CAN Shield Help

Post by cavemaneca » 2015 Feb 09 22:00

I was able to find a library for the arduino board that can do 83kbps, but I still couldn't get it to turn on, and I don't have anything to test if it's working. Best bet would be to hook it up to the car on receive and see if it gets the power signal for the radio.

nr0x
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Re: Arduino CAN Shield Help

Post by nr0x » 2015 Feb 26 11:45

Ok, so pretty much the same thing as my Jeep then. Sorry I can't help with Arduino...I'm a picaxe guy. But My best guess would be 125k/11bit ID. On an ELM327/clone that would be Protocol B (AT SPB/n).

OBDRipper
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Re: Arduino CAN Shield Help

Post by OBDRipper » 2015 Mar 04 16:00

My jeep connects at 125kbps on the interiour bus, and im tapping into the radio's can-bus wires.

The shield you have is pretty much the same thing compared to seeedstudio, which i have.
Right above the green can-bus (can-h & can-l) there are some termination resistors that you sometimes need to de-solder,
However i reccomed you put in a switch.

See this http://www.techtinker.co.za/forum/viewt ... 8&start=20

Some cars need the node to be terminated and some dont, if not it WILL not communicate at all.
Also on my jeep if you connect the shield in at the wrong speed it will distort the whole bus causing and error, fundamentals of serial communication, it basically causes a corruption and you need to reboot it by switching off and on again.

Hope this helps

Audiodoc81
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Re: Arduino CAN Shield Help

Post by Audiodoc81 » 2018 Aug 13 21:06

Does anyone know where I can find an Arduino library that can do 83.3 kbps?

nemiro
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Re: Arduino CAN Shield Help

Post by nemiro » 2018 Aug 18 11:07

I am not using the shield, but I did a project using a Teensy 3.2 (and Teensyduino), and it runs 83.3k without issue. Teensy has CAN capabilities built in. Still need the CAN interface chip, but the protocol is already there.

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