This calls out for an FPGA solution.

On Thu, Feb 22, 2018 at 10:45 PM, Forrest Christian (List Account) <
li...@packetflux.com> wrote:

> You can get a fpga board which might be suitable for this project (after
> adding appropriate clocks) for around $20 anymore.   One example:
> http://tinyfpga.com/
>
>
>
> On Thu, Feb 22, 2018 at 6:42 PM, Lewis Bergman <lewis.berg...@gmail.com>
> wrote:
>
>> They aren't cheap but you could always use an fpga.
>>
>> On Thu, Feb 22, 2018, 7:35 PM Chuck McCown <ch...@wbmfg.com> wrote:
>>
>>> No, I saw it, but I already had the Pi so I ignored it and hoped for the
>>> best.
>>> I tried it first with arduino.  Just not enough speed.  And it had the
>>> jitter problem too.
>>>
>>> I have a method using three TTL/CMOS chips that is going to work... I
>>> think...
>>>
>>> The only thing separating the gps disciplined signal and the T1 will be
>>> a D flip flop and a few AND/NAND gates.  So that ought to get me super low
>>> jitter.
>>>
>>> Trying for stratum I with rubidium hold-over isochronous performance at
>>> the end of the day.  For cheap.
>>>
>>> *From:* Forrest Christian (List Account)
>>> *Sent:* Thursday, February 22, 2018 6:27 PM
>>> *To:* af
>>> *Subject:* Re: [AFMUG] OT Raspberry PI
>>>
>>> Ok, I think you missed this portion of my email last time:
>>>
>>>
>>> *"I'm skeptical that you'll be able to generate a bitstream with enough
>>> accuracy under Linux, without extreme programming measures.I'd suggest a
>>> digilent chipkit wifire and the arduino ide for this.  You should be able
>>> to bitbang at least a T1 with this processor (500mhz)"*
>>>
>>> Generally the raspberry pi is great for 'tiny server stuff', or 'user
>>> interface' stuff, and the arduino and/or microcontrollers will work better
>>> for what you're looking at, since there isn't an operating system in the
>>> way.  All arduino really is is a c++ ide with some simplified libraries.
>>>
>>> The wifire product I mentioned is really a PIC32MZ dev board, optimized
>>> for arduino.  If you've had enough of the arduino ide, you can download the
>>> microchip ide and program it with a full development kit.
>>>
>>> Honestly for what you are talking about a EUSART in even a low end PIC
>>> might be able to handle this.  If you program the EUSART into synchronous
>>> mode you'll just have to stuff a byte into it every 8 bit times and it will
>>> clock it out for you.  Not sure if the clock rate is adjustable enough for
>>> you, but if you get a PIC with the NCO peripheral you might be able to
>>> dynamically adjust the frequency enough to make it work.
>>>
>>> NCO app sheet:  http://ww1.microchip.com/downl
>>> oads/en/AppNotes/90003131A.pdf
>>>
>>>
>>>
>>>
>>> On Thu, Feb 22, 2018 at 3:48 PM, <ch...@wbmfg.com> wrote:
>>>
>>>> Anyone know how to get my program to run on bare metal?
>>>>
>>>> Or at the very least tell Linux that my program is the most important
>>>> thing in the world and service it above all other things.
>>>>
>>>> I am trying to create a timing signal with the Pi.  It is doing it but
>>>> the jitter is pretty bad.
>>>>
>>>> I have researched trying to use an interrupt but there is a pretty low
>>>> limit on how many times per second you can fire a hardware interrupt.
>>>> Too low for my application.
>>>>
>>>
>>>
>>>
>>> --
>>> *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.*
>>> Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602
>>> <https://maps.google.com/?q=3577+Countryside+Road,+Helena,+MT+%0D+59602&entry=gmail&source=g>
>>> forre...@imach.com | http://www.packetflux.com
>>> <http://www.linkedin.com/in/fwchristian>
>>> <http://facebook.com/packetflux>  <http://twitter.com/@packetflux>
>>>
>>>
>
>
> --
> *Forrest Christian* *CEO**, PacketFlux Technologies, Inc.*
> Tel: 406-449-3345 | Address: 3577 Countryside Road, Helena, MT 59602
> <https://maps.google.com/?q=3577+Countryside+Road,+Helena,+MT+59602&entry=gmail&source=g>
> forre...@imach.com | http://www.packetflux.com
> <http://www.linkedin.com/in/fwchristian>  <http://facebook.com/packetflux>
>   <http://twitter.com/@packetflux>
>
>

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