Re: Linux board with 10 CANs

[Gediminas Simanskis <gediminas@8devices.com>]

Hi,
GPL2
Gediminas

On 2015-05-18 16:31, Bernd Krumboeck wrote:
> Hi Gediminas!
>
>
> Can you tell us the license of the source code from usb2can firmware?
>
>
> regards,
> Bernd
>
>
> Am 2015-05-18 um 11:07 schrieb François Beaulier:
>> Le 15/05/2015 15:54, Bernd Krumboeck a écrit :
>>> Hi!
>>>
>>>
>>> I don't know much about this things, but what do you think about 
>>> following:
>>>
>>> Use two 4 port usb hub (MICROCHIP USB4624I-1080HN) with 8 x 
>>> STM32F072 or STR750FV2.
>>>
>>> You can flash the MCUs under linux with dfu-util 
>>> (http://dfu-util.sourceforge.net/).
>>>
>>> A firmware for STR750FV2 is available here (please check license):
>>> https://github.com/krumboeck/usb2can_firmware
>>>
>>> I don't know if it works, but there is also a gcc version available:
>>> https://github.com/krumboeck/usb2can_firmware/tree/gcc-test
>>>
>>>
>>> If you use this firmware or at least the same procotol, then the
>>> hardware will be compatible with usb_8dev can driver.
>>>
>>>
>>> regards,
>>> Bernd
>>>
>>>
>>
>> Hi Bernd,
>>
>> Thank you for pointed out this USB solution. I didn't know such 
>> firmware existed.
>> I looked in the gcc-test repository, and apart from ST files the 
>> license is not specified.
>> Can you tell us more about license ?
>>
>> Francois
>>
>>
>>>
>>>
>>> Am 2015-05-15 um 09:56 schrieb François Beaulier:
>>>> Hi,
>>>>
>>>> I'm starting the design of a CPU board, based on a computer on 
>>>> module with a very common SOC like i.mx6 or am335x.
>>>> I need to fit my board with at least 10 CAN ports, may be more. 
>>>> (The SOC have 2 CANs so i need 8 more)
>>>> The board will run with Linux and of course i want a socketcan 
>>>> interface for each bus !
>>>> CAN bitrate needed is quite low (50kbps) and latency is not 
>>>> critical but bus load may reach 100% sometimes.
>>>> As far as possible i want to avoid driver development, or just 
>>>> doing slight modifications on an existing driver.
>>>> I don't want to use MCP2515, i had trouble with it on a previous 
>>>> design because of the lack of buffer in the chip.
>>>> I can't imagine putting 8 MCP2515 and not missing any frame, but 
>>>> may be i'm wrong ?
>>>>
>>>> Here are the options i have considered, they involve using external 
>>>> MCUs to provide enough CAN interfaces :
>>>>
>>>> - MCUs with SLCAN : SLCAN have the advantage of simplicity and it 
>>>> should offer enough performance at low data rate. Problem is that 
>>>> it would require 8 UARTS. I could modify SLCAN driver to allow 
>>>> multiple CAN channels on the same UART, and so use MCUs with 
>>>> multiple CANs, does it sounds reasonable ?
>>>>
>>>> - MCUs with SPI 1 : adapt MCP2515 driver in a way to make the SPI 
>>>> protocol manageable on the MCU side (SPI slave). The MCU will be 
>>>> able to provide the buffer for CAN frames that the MCP does not 
>>>> have. This option is just a way of trying to go fast, it is not 
>>>> very elegant, and have the limitation of one CAN channel per SPI 
>>>> connection / driver instance.
>>>>
>>>> - MCUs with SPI 2 : use the Stefano Babic SPI driver posted on this 
>>>> list. This is probably the best choice for a long term and more 
>>>> generic solution. But i'm afraid it may require too much work to 
>>>> complete. What is the status of this driver right now ? Does anyone 
>>>> have an idea of the remaining work to do to make it ready for 
>>>> mainline ? Stefano are you available to spend more time on it ? I'm 
>>>> also wondering whether multiple instances of the driver can run 
>>>> concurently if i put more than one MCU ?
>>>>
>>>> Concerning the MCU software i could release it as an open-source 
>>>> project, anyone interested in participating ?
>>>> I'm very familiar with STM32 MCUs so i will probably use an 
>>>> STM32F072 (low cost cortex M0 with one CAN).
>>>>
>>>> Any idea or advice is welcome, thank you for reading this much too 
>>>> long post.
>>>>
>>>> Regards
>>>>
>>>> Francois Beaulier
>>>> www.ingelibre.fr
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>>>
>>
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