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> > >
