Re: Visit

Tx priority.
This can be achieved by defining multiple FIFO's with different
priorities. The CAN controller in the Microchip PIC32 has this done in
hardware. Up to 32 FIFO's with flexible depth of 1 to 32 messages can be
defined as either Rx or Tx FIFO. The Tx FIFO's have 4 levels of priority.
If the CAN controller does not have an internal Tx FIFO, this mechanism
can be implemented in the driver.

Kees


Op 19-11-2016 om 20:12 schreef Simon Byholm:
> Hello John
>
> One thing I've noticed is that CAN driver implementations usually
> use a fifo style send buffer, letting low priority messages block the
> queue, when there's a higher priority message that should really
> be sent first.
>
> Some discussion on this would probably be useful.
>
> Simon
>
> Simon Byholm - Software Manager / Quality Manager
>
> Phone: +358 6 357 6306
> Fax: +358 6 357 6320
> email:[email protected]
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>
> TK Engineering solves your CAN, CANopen, J1939 and NMEA2000 problems by providing the hardware, software and know-how you need to design, manufacture and troubleshoot your industrial and heavy machine CAN networks. Call +358 6 357 6300 or [email protected]  to learn how we can help you solve your CAN related problems.
> On 19.11.2016 11:46, John Dammeyer wrote:
>>
>> Hi everyone,
>>
>> I know this isnÂ’t directly CAN bus related but I had the pleasure of 
>> a visit with Lars-Berno Fredriksson from KVASER today.Been a few 
>> years since I met him.Got caught up on all the CAN and CANFD things 
>> that his company is doing.
>>
>> As we discussed the olden days when even CAN drivers werenÂ’t 
>> available yet, I realized how much I missed the detailed discussions 
>> on the working of the CAN bus.ItÂ’s true though, there are many 
>> experts out there now who have lots of experience and the internet is 
>> full of reference information that wasnÂ’t around 20 years 
>> ago.Companies like Microchip have their own forums and often people 
>> interested in the CAN bus never even make it to this list.
>>
>> Browsing through some of the messages from the comp.arch.embedded 
>> UseGroup in 1995, the names of the contributors are Ken Tindell, 
>> Edwin Armstrong, Olaf Pfeiffer, Stephen Pelc and there is a rich 
>> amount of information about CAN.Ken Tindell started this list that 
>> was eventually and is now graciously supported and maintained by Vector.
>>
>> IÂ’ve been asked a number of times to put my experience down into 
>> either a book or a series of essays on CAN bus.IÂ’ve been fortunate 
>> enough to have had a set of interesting experiences.Even to being on 
>> a team developing and extension of the CAN bus to run on powerline 
>> and deliver Ethernet Connectivity with up to 4K byte packets between 
>> the arbitration and the CRC.In many ways CAN FD is a subset of that 
>> original design.
>>
>> Anyway, IÂ’d like to get some feedback on what might be interesting in 
>> a book or a series of essays.ThereÂ’s already lots on the low level 
>> stuff.Less on High Level Protocols and whatÂ’s there is often deep 
>> into the details.Maybe more implementation examples and how itÂ’s done?
>>
>> So the floor is open.LetÂ’s have a discussion on what isnÂ’t well 
>> documented.
>>
>> Thanks
>>
>> John Dammeyer
>>
>> "ELS! Nothing else works as well for your Lathe"
>>
>> Automation Artisans Inc.
>>
>> http://www.autoartisans.com/ELS/
>>
>> Ph. 1 250 544 4950
>>
>

-- 
Kees Zagers
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5674 TE  NUENEN