Re: CAN controllers

On 2007-06-29, Michael <nleahcim@xxxxxxxxx> wrote:
On Jun 29, 3:14 pm, Hans-Bernhard Bröker <HBBroe...@xxxxxxxxxxx>
wrote:
Michael wrote:
Hi there - on an upcoming project I will need to use a CAN controller.
I have previously used the Microchip MCP2515. What other CAN
controllers are there out there? All I know of is the NXP SJA1000. Any
opinions on advantages of one over the other?

By far the biggest advantage to be had is to use a CAN controller
integrated with a microcontroller, not as a separate chip. Stand-alone
CAN controllers will take considerable resources just to connect them to
the micro: read/write message box control and data registers, route
interrupts, do access control and all that. CAN itself is just two
wires taken care of by the CAN controller. A lot simpler.

I agree, for the most part. Though really the MCP2515 did not take all
that many cycles when I used it. It generates an interrupt when a
message is received. The ISR starts the DMA reading in the message.
The DMA generates an interrupt when it finishes.

I've also been told that that simply is not an option, as all of our
code is written for a very specific line of chips.

It's also not an option for cost sensitive applications. Using
a uC+MCP2515 was about half the cost of an equivalent uC with
integrated CAN.

I have to go with an external CAN controller.

I could have used an integrated one for another $5...

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