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/downloads/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
forre...@imach.com | http://www.packetflux.com
<http://www.linkedin.com/in/fwchristian>  <http://facebook.com/packetflux>
<http://twitter.com/@packetflux>

Reply via email to