A20 som can bus

[AzHofi]

Hi guys,
can someone point me how to enable and use can bus on a20? I use MCP2551 transceiver connected, but what should I configure on debian to use lincan infrastructure? Thanks in advance,
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Attila HOFFEREK

[JohnS]

I've not heard of any support for it yet.

John

[AzHofi]

Finally I recompiled the kernel with mcp251x support and assembled a can receiver circuit using mcp2515 - mcp2551 combo, on SPI bus. Thanks.

[bruceuk]

Hi AzHofi ....any chance you could post a schematic and how you connected to the EVB....or the SOM?

Why did you need mcp2515? I think the A20 already has a single CAN controller, should be able to just attach mcp2551?


Bruce

[AzHofi]

Hi Bruce,

Hi AzHofi ....any chance you could post a schematic and how you connected to the EVB....or the SOM?

I used microchip's officially recommended schematic with a 16MHz crystal. I connected it to spi-1 bus wired to uext connector on evb.

Why did you need mcp2515? I think the A20 already has a single CAN controller, should be able to just attach mcp2551?

Because I don't know which driver to compile and use in debian linux kernel. Can You point me? I'd be very happy to use a20's own can facility with linux kernel lincan infastructure.

Thanks in advance,
--
Attila HOFFEREK

[pankajmisra]

Hi AzHofi,

I am able to compile mcp251x.c driver & inserted in kernel. Driver probed properly.

But problem is that Canutils programs are not able to drive it.

Candump never shows any output in loopback mode.

Were you able to check can communication on MCP2515 ?

[bruceuk]

>> Because I don't know which driver to compile and use in debian linux kernel. Can You point me? I'd be very happy to use a20's own can facility with linux kernel lincan infastructure.

Afraid I have no idea .... I did some digging and found absolutely nothing.....doesn't look like anybody is using the CAN controller in AllWinner processors ...kinda sad really, maybe Olimex can throw some weight behind an official question to AllWinner?

[bruceuk]

Just found this:
https://github.com/btolfa/sunxi-can-driver

[bruceuk]

Forked it for safe keeping and added the pdf which may be the documentation:

https://github.com/BruceBushby/sunxi-can-driver

[AzHofi]

Forked it for safe keeping and added the pdf which may be the documentation:

https://github.com/BruceBushby/sunxi-can-driver

Thanks, but this is for android kernel, not debian or something. If I had some time I'd test and port it.

[AzHofi]

Were you able to check can communication on MCP2515 ?

I was. Did you use the previously suggested schematics? Could You post a drawing how do You try to use it?

[pkm2kor]

Hello,

Are you able to communicate on MCP2515 on multiple baudrates.

I am able to communicate on 250K but i am not able to establish communication on any other baudrate.
Setting any other baudrate results in error frames.
I am using ip & canutils as user application to do settings & send receive data.

I am using sunixi-linux on olimex a20 olinuxino micro.

[dave-at-axon]

What is your sampling points and sync jump width set for? Are they the same across different bit rates?

CAN with the same baud rate doesn't mean it will talk if the sampling points are different.