I'm almost done with my minimize raw CAN 2.0A (11 bit) running in the Arduino Due with a sample sketch. I'm expecting to receive the transceivers in a couple of days (TI SN65HVD234 & SN65HVD235) and build a shield. In the meantime I've hooked CANRX0<->CANRX1 and CANTX0<->CANTX1 for looping tests. I hope by mid-next week to upload in github the raw CAN code for revision and comments. Thank you for your patience.
I think this should be the basic foundation of the DUE-CAN library.
Oh please, don't miss the opportunity of calling it the CAN-DUE library, we need more nerd humour around here. LOL
Lefty
"No CAN due-sville, babydol" ?
Wow Palliser - you seem to be really focused on this thanks for spearheading!
I haven't heard of CAN protocol until reading this thread, so I am wondering (just in case I'm missing out on learning some interesting things):
What is "CAN protocol" used for? Automotive applications were mentioned (so I assume car odometer, engine status, etc.), but what other applications can it be or is commonly used for?
Hello giantsfan3. In my case, I started getting interested in the CAN protocol after been involved for over a year integrating a German Battery Manager System (CAN) with a PLC (Modbus RTU). Then, I understood why CAN is one of the most reliable communication protocols I ever seen. In the particular case of the microcontroller inside of the Arduino Due (SAM3X8E), there are about one hundred configurable registers! (status, interruptions, errors, etc.). The CAN protocol has been around for more than 25 years. Just two wires, it offers high-speed communication rate up to 1 Mbits/sec thus allows real-time control. CAN can theoretically link up to 2032 devices (assuming one node with one identifier), excellent error handling and fine fault confinement. Used to operate in robust, electromechanical (noisy) environments like in automotive, also in medical apparatus, textile machines, elevators, agricultural and nautical machinery. There are other CAN-based higher layer protocols like CAN Application Layer (CAL), CAN Kingdom, CANopen and DeviceNet.
Just Google it or Wikipedia. You can check the following compendium of the CAN protocol and uses in the automation industry.
http://www.diakom.com.ru/el/communication/can/can_org.pdf
We hope soon, see Arduino Due fans contributing with new cool CAN applications. Regards.
Implementing the CAN physical layer.
For the implementation of the physical layer of the Arduino Due CAN interface, we need a mean to translate the CAN messages to/from differential signals across a physical medium such as a twisted pair cable.
CAN transceivers provide that differential physical layer interface between the data link layer (CAN controller inside the SAM3X8E) and the physical wiring of the CAN bus.
CAN has only two bus voltage states; recessive (driver outputs are high impedance) and dominant (one bus line, CANH, is high and the other, CANL, is low), unlike the traditional differential data transmission where a logic 1 is transmitted as a voltage level high on one noninverting transmission line and low on the inverting line. Correspondingly, Logic 0 is transmitted as low on the noninverting line and high on the inverting line.
For obvious space reasons, we need a shield to mount the transceivers, some pull resistors, capacitors and the CANL CANH connectors.
I have chosen two SN65HVD234 CAN transceivers for my first shield (I am considering to use 235's later). Because I am prototyping, for the board I will use a SchmartBoard (RadioShack 2760259). The shield will provide 2 can ports (CAN0 and CAN1).
Here a picture of the transceivers circuit. It's very simple, just a straight connection with the arduino CAN ports. Later on, I have planned to use some features of these transceivers like high-speed and low power modes that will required 4 more Arduino Due pins (2 EN and 2 RS).
Regarding the code, I already have my Arduino Due talking CAN 2.0A but a library optimization is required before upload the files in github. Thank you again for your patience and keep looking out my post.
Hello,
"Long-time listener/first-time caller" here... I just wanted to point out an interesting discussion regarding use of an Arduino-compatible 32-Bit board (the ChipKIT) and a CAN Communication Interface for the Ford Motor Company called OpenXC (http://openxcplatform.com/). The discussion forum can be found at Redirecting to Google Groups
I have no idea if there's any way these two efforts can be of use to each other, but I figured I'd mention it...
Keep up the exciting work!
Hello roundhouselabs and welcome to the forum. Thank you for the information. So far, my Arduino Due can transmit/receive CAN 2.0A messages within the Arduino API. I used an Atmel sample code for the SAM3X series. Right now, I am organizing the library and replacing missing functions presents in Atmel but in the Arduino API and hope to release them with a couple of sample sketches in github in the coming days for revision and comments. As you may have noticed, a CAN shield has been required. Regards!
Here a picture of my Arduino Due CAN shield (prototype) during loop tests. I will mount the resistors in the shield (less power of course!)
I'm excited to see work with CAN on the Arduino Due - I'm one of the developers of the OpenXC platform that roundhouselabs mentioned (openxcplatform.com) and while we started prototyping with the Arduino at Ford, we had to move to the chipKIT to get a little bit more performance and CAN controllers on the MCU. I'd love to get the OpenXC translator working with the Due; all we really need is the library API - I read through this thread but I can't quite tell if there is progress happening somewhere else on the software side.
If there's a work-in-progress repository somewhere, I'd love to help out. Looking for examples of simple CAN APIs that would exist at about the same level of abstraction as the other core Arduino libraries, the one provided by the mbed library may be a good start: CAN - Handbook | Mbed
CAN Shield - Due electrical schematic.
Arduino Due and CAN shield with termination resistors (120 ohm) mounted. The jumpers are selecting high-speed (0V-black) and disabling low-power (3V3-red) modes in the SN65HVD234 transceivers. The CANH (orange) and CANL (purple) bus terminals hooked for a loop test.
I was able to order a DUE today, so I'll join the ranks soon
I really appreciate it, that you use both CAN-Transceivers! This will be great for using it as a Gateway!
I have my Due and now it's time to order the transceivers. I'm going to get both the 234 and 235's. Which ever ones I don't use in the car I'll use on the work bench. Thanks for tackling this.
Great for you keija and that_kid. Do as I did: Request a couple of samples of each transceiver to Atmel. I have some sample sketches running OK on my Due, using a combination of Atmel and Arduino library files. The goal is to occupy as much as Arduino files and as less as Atmel files as possible. I also hope to run my first real test these next days interfacing Due with a battery manager system (with XC167CI - by Infineon and AT91SAM7).
I wanted to share another of the tests I am working now with Arduino Due using the CAN shield. The test consists of making Due read CAN data from a commercial OBD II code reader. This will prepare the ground for more tests like convert Due as a OBD2 simulator system generating some DTC codes to be read by the code reader and finally to make Arduino Due read some real DTC codes from my car (Honda-Oddysey 2002) or any other car under OBD2.
As some of you know, ODB II stands for On Board Diagnostics, level 2. OBD II is a federally mandated engine & emissions management standard for all passenger cars sold in 1996 and beyond. ODB II uses CAN bus Dual Wire like Arduino Due (ISO 11898-1/SAE J2284).
For my first test I used an Actron CP9125 pocket scanner (with a 89C71CC01CA microcontroller and TJA1050 CAN transceiver).
Here a the schematic of interconnection between the code reader and Arduino Due and a picture of both systems. So far, Due can read from the reader ID 0x07DF the following data: 02 01 00 99 99 99 99 99 which is a request data to start reading DTC codes. I am very excited exploring CAN protocol in Arduino Due and OBD2 systems. I'd recommend to get ready if you want to embark on this journey.
Excellent news, I'm just waiting on my parts to arrive from mouser.com I was going to order the engineering samples but I needed some parts so I just went ahead and get it all. Next stop is to see if my local radio shack has the shield that you are using.
Hey guys. I'm interested in getting on board with the CAN protocol as well. I've done a lot of low level CAN drivers on the pic24, dspic, and pic32 along with the MCP2551 transceiver at work. I have a DUE coming in next week and just put in my order for TI samples of the two transceivers mentioned earlier in this thread (234 and 235).
What is the scope of this CAN library? I'd be more than willing to work the low level driver stuff and different implementations of it (interrupt based, polling based, different modes).
Hello downtown_sausage and welcome aboard! We are going to need your CAN skills soon. So far I have Due running CAN 2.0A but with a mixed Arduino-Atmel library. I hope to release a couple of simple sample sketches and a tentative CAN library in github very soon. I am following guidelines/advices from the Arduino team and Atmel but everybody is welcome here. The scope: once released the CAN library, we'll need as much people as possible to be involved and contribute with ideas, applications, improvements, fixing bugs, etc... remember, this is the first Arduino board with embedded CAN controllers: just transceivers between the board and real CAN device, so, a new Arduino Art is oncoming and a lot of work to do. Thanks!
Palliser, you might consider doing your development in the open on GitHub, even before you think it's at a good draft stage. No reason we can't start helping you out already!