BSP for Microchip ATSAMA5D27-SOM1-EK1

[Christian Mauderer]

Hello Peter,

Thomas mentioned already the bug that has been reported to Microchip.
Please note that I had two more problems with the BSP on another
customers board:

- The core clock couldn't be set to the maximum frequency from the data
sheet. Both possible configurations for that frequency didn't work. The
first one would have set the PLL to the same frequency as the CPU core
clock. With that the system was not stable. The other setting (a divider
of two after the PLL) seemed to work better but that forced me to set
the PLL to a higher frequency than the data sheet specified. I ended up
with the lower frequency.

- The external SDRAM seemed to introduce some jitter into the core PLL
too (not only in the USB PLL which was the reason for the USB bug). With
higher frequency configurations the system sometimes had an odd
behaviour: A comparison went wrong when it should go well. Again that
lead to a slightly lower frequency that seemed stable. So the board now
runs on only about two thirds of the maximum frequency specified by
Microchip.

If you still want to use the ATSAM chip: Microchip managed to get a
better community around the libraries that are used in the BSP for that
chip. There is a newer version of them somewhere on github. If there is
funding for it, I would suggest to update the ones that are integrated
in the ATSAM BSP by the newer ones. They contain quite some bug fixes.
But it will need some work to do that.

With kind regards

Christian Mauderer

Am 25.11.18 um 19:42 schrieb dufault at hda.com:
> Thank you for the advice.  I will not need USB, but will need SDRAM and
> don’t need poor support.  Microchip? You tried to push RTEMS for this
> platform tied to space applications, are you monitoring this?  The
> platform looks like just what I need but not if you’re not supporting it.
> 
>> On Nov 25, 2018, at 13:23 , Thomas Dörfler
>> <thomas.doerfler at embedded-brains.de
>> <mailto:thomas.doerfler at embedded-brains.de>> wrote:
>>
>> Peter,
>>
>> just to make you aware: we designed a board with the ATSAMV7 chip and
>> hit some nasty and at least one really ugly bug: operating the USB
>> interface concurrently with external SDRAM does not work. Half a year
>> after reporting this bug, Microchip confirmed it, but did not plan any
>> fix for it. BTW: The conbination (USB+SDRAM) was also available on
>> Microchip's evaluation board, but obviously was not tested together at
>> Microchips labs...
>>
>> So: I recommend you to tripple check, whether the ATSAMA5 meets all of
>> your expectations.
>>
>>
>> Kind regards,
>>
>> Thomas.
>>
>> ----- Ursprüngliche Mail -----
>> Von: "Peter Dufault" <dufault at hda.com <mailto:dufault at hda.com>>
>> An: "Development" <devel at rtems.org <mailto:devel at rtems.org>>
>> Gesendet: Sonntag, 25. November 2018 18:38:19
>> Betreff: BSP for Microchip ATSAMA5D27-SOM1-EK1
>>
>> I need to evaluate this for a multi-chip application.
>>
>> This part is a result of Microchip’s take-over of ATMEL.  I’m
>> double-checking that to create a BSP based on this I should start with
>> the existing ATSAMV7 BSP, I think the peripherals (e.g. network chip
>> and so on) are the same as the existing ATSAMV7 port.
>>
>> Peter
>> -----------------
>> Peter Dufault
>> HD Associates, Inc.      Software and System Engineering
>>
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>> -- 
>> --------------------------------------------
>> embedded brains GmbH
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>> Germany
>> email: Thomas.Doerfler at embedded-brains.de
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> 
> Peter
> -----------------
> Peter Dufault
> HD Associates, Inc.      Software and System Engineering
> 
> This email is delivered through the public internet using protocols
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