Had the command syntax wrong.
But got nice to work. Have to sudo if you use negative nice numbers.
It made zero difference in my jitter. I went from 19 to –20 on nice and no
change.
From: ch...@wbmfg.com
Sent: Thursday, February 22, 2018 4:29 PM
To: af@afmug.com
Subject: Re: [AFMUG] OT Raspberry PI
The problem is there is a crap ton of stuff out there that needs network sync.
And it all has a T1 as an input.
But most T1 trunking circuits are getting replaced with SIP.
So, I am building a cheap and dirty T1 signal generator that is GPS and
rhubidium referenced. The hard part is easy. The easy part should be easy but
all the T1 framing chips that used to exist no longer exist.
The ones that are out there have massive CPU interfaces and tons of registers
that need to get set to get them fired up and running....
Where is Exar when you need them....
From: Adam Moffett
Sent: Thursday, February 22, 2018 4:21 PM
To: af@afmug.com
Subject: Re: [AFMUG] OT Raspberry PI
Tell whoever's got the T1 that 1967 is way behind us and get a new interface.
Problem eliminated LOL
------ Original Message ------
From: ch...@wbmfg.com
To: af@afmug.com
Sent: 2/22/2018 6:16:45 PM
Subject: Re: [AFMUG] OT Raspberry PI
I have to generate an alternate mark inversion signal on 1.544 MHz with every
193rd bit following a t1 framing sequence.
Sure wish a 555 could do that.
From: Dave
Sent: Thursday, February 22, 2018 4:10 PM
To: af@afmug.com
Subject: Re: [AFMUG] OT Raspberry PI
Find a 555 timer ... I used many in the olden day when radioshacks were king
LOL!
On 02/22/2018 05:05 PM, ch...@wbmfg.com wrote:
I am thinking of using some shift registers instead of using the PI output
directly as the timing signal.
Use the PI to load them.
I love me some hardware design anyhow....
From: Colin Stanners
Sent: Thursday, February 22, 2018 3:59 PM
To: af@afmug.com
Subject: Re: [AFMUG] OT Raspberry PI
Other than setting the process priority, you may need a custom kernel. See
https://medium.com/@metebalci/latency-of-raspberry-pi-3-on-standard-and-real-time-linux-4-9-kernel-2d9c20704495
On Feb 22, 2018 4:48 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.
--
