Re: MCP2515 implementation is slow

[gianluca <gianlucarenzi@eurekelettronica.it>]

On 11/25/2014 05:19 PM, Pankajkumar Misra (RBEI/EEA2) wrote:
> Hello Guys,
>
> I have compiled MCP251x.c kernel driver module for Olimex A20-Olinuxino Micro.
>
> The device is working fine for one frame at a time at 500ms. If I send two or more frame at the same time,
> CAN is going to bus-off due to overrun errors.
> Even if I send one frame at faster rate say, 100ms,results in bus-off.
>
> I am communicating with module with ip commands, cansend & candump.
> Also my SPI module is working only at 250K baud, not any other baud.
>
> Any suggestions.
>
> Best Regards,
> Pankaj
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>

Once upon a time there were a custom mcp2515.c driver rewritten by 
Oliveira and modified by myself to obtain the maximum performance 
possible with this VERY POOR chip.

http://clientes.netvisao.pt/anbadeol/mcp2515.html

If you are interested, please feel-free to contact me to obtain a 
modified version (maybe better? :-P ) of this driver.

Actually it runs on a 2.6.27 kernel with a Samsung S3C2442 SoC. It runs 
without any problem running @ 250Kbit/s and 125Kbit/s with some burst of 
a frame every 2 or 4 msecs. For sure your application has to be 'niced' 
to a be almost-real-time over other processes and the socket receive 
queues have to be increased a little bit.
But it works good over the past 3 years with approx. 1k custom boards 
batch worldwide sold.

It would not so difficult to adapt it to run over a 3.x kernel and maybe 
in a near future I will add a DEVICE TREE support for it.

Best regards,
-- 
            ,,,
           (o o)
======oOO==(_)==OOo======

Gianluca Renzi
R&D
phone: +39.0542.609120
fax:   +39.0542.609212

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