Controller Area Network

[Utsav Drolia]

Could someone please suggest a good book for Controller Area Network,cos there are loads of them and i cant decide which to refer..
Thanks

Utsav
Formula Manipal

[Utsav Drolia]

Could someone please suggest a good book for Controller Area Network,cos there are loads of them and i cant decide which to refer..
Thanks

Utsav
Formula Manipal

[Julian Choquette]

You should start with the official reference: The Bosch CAN Specification.

Available for free on the Bosch website: http://www.semiconductors.bosch.de/pdf/can2spec.pdf

[Utsav Drolia]

I have been through this document and it describes the protocol.
But it does not have any examples.
Thats the reason I wanted to check a text book,cos it wud have explained the implementation through an example.

Utsav
Formula Manipal

[jrickert]

What exactly do you want to build. What part of CAN do you have questions about that the internet can't easily answer? I'm working on an information cluster that uses CAN to get data.

[Utsav Drolia]

What I basically cannot understand is what is DeviceNet,CANopen,SAE J1939-What exactly are they?
As in once i have the transceiver and the controller,cant i use these with a Microcontroller with c code?I think i can do that hence i dont understand where CANopen etc come in.

[jrickert]

Device Net and CANopen are both industrial protocols built on top of the CAN physical layer that have little to do with anything automotive related. J1939 specifies a complete automotive CAN implementation from the electrical signaling all the way to the shape of a diagnostic connector and the messages that are exchanged by devices on the bus. The hardware for all of these should be the same as far as any circuit you might be thinking of building goes. I wouldn't really bother complying with any of these. The reason these standards were written was so that devices from different manufacturers can inter operate. So far as i have seen interoperability through standard protocols doesn't really happen in the automotive aftermarket. In the case of an SAE car the only use i can see for CAN is linking together some combination of Dash, ECU, PDU DAQ or Telemetry. Most of these devices have their own application layer protocols in mind that you must follow. Chances are if you are posting on this forum and asking about CAN you are constructing one of the above black boxes.

[Utsav Drolia]

That is exactly what i hope of doing and thats exactly the confirmation i was looking for,that i do not need to comply to any of these.
Another doubt is that in my code,do i need to construct the entire frame of the message or i just need to provide the data to the controller and it will construct the rest of the frame?
Thanks a bunch,you've been great help. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[screwdriver]

I hope you don't think about implementing a can-bus interface on the general-purpose IO pins of your controller. That would be reinventing the wheel.
Your controller should come with CAN support built in. Usually it has a CAN TX and a can RX pin. In order to put these two pins through to the CAN-HIGH and CAN-LOW lines, you need a driver chip. Microcontrollers with CAN support usually come with some kind of API to use the capabilities. The API takes care of all the stuff on the physical layer for you, so you only need to think about the payload and frame type.

[ERS]

Josef,
I understood from Utsav's post that he already had the transceiver chip.

Utsav - the code for implementing CAN - initialising a frame etc will vary depending on the micro you're using

Most likely there will be a driver library available (my experience was using Atmel an AT90CAN chip linked to Atmel transceiver, freely available and pretty well documented). With this you'll just have to understand their message format etc to send or receive. You'll have to tell it data length, address to send to, and the data at the very least.

There's a lot of documentation out there, it's a bit hard to dive into straight off.

[Utsav Drolia]

Ok...
Now I have a rough idea of what to do.I'll buy the components and meddle around with them. I guess thats the best way to understand anything to the fullest.
Thanks a bunch Josef,ERS.

Utsav
Formula Manipal