Bob,
Did Atmel (AVR) kill your dog or something?
They have some pretty powerful MCU's. Are you flatly stating that none of
them could be used for a "very nice GPSDO"?
Dale
Just fooling around, no offence intended.
-----Original Message-----
From: Bob Camp
Sent: Thursday, December 06, 2012 1:57 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] GPSDO Alternatives
Hi
That is where most of these tools were many years ago. Competition has
forced them to open things up quite a bit. You can code a very nice GPSDO
and not use anything but freely available tools. You can do it on several
processors, none of which come from AVR (and thus use the Arduino chain).
Bob
-----Original Message-----
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Dale J. Robertson
Sent: Thursday, December 06, 2012 1:47 PM
To: Discussion of precise time and frequency measurement
Cc: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] GPSDO Alternatives
Most of the "free" tool chains are not truly free I.e. open source including
all libraries and coupled with an open source compiler and debugger. In
addition few of them are currently offered in hobbyist friendly DIP
packages.
Once you resign yourself to having to build hardware glue for some of the
special functions required, CPU performance becomes mostly a non issue. For
quick and dirty lash ups on perf board (as I believe the OP is looking for),
It's hard to beat a pic or Avr and for code re-use from a large online
community it's hard to beat the arduino eek-o-system
Dale
Sent from my iPhone
On Dec 6, 2012, at 1:00 PM, "Bob Camp" <li...@rtty.us> wrote:
Hi
It's a rare microcontroller these days that does *not* come with a free
tool
chain. Same goes for the debugger. Most MCU lines have family members with
similarly low (or lower) prices and good availability. They pretty much
all
either work with a crystal two caps and a resistor. Most will run fine
with
none of the above on the internal clock.
Bob
-----Original Message-----
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Dale J. Robertson
Sent: Thursday, December 06, 2012 12:45 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO Alternatives
Arduino is Dirt Cheap!
At it's cheapest it is just an atmel AVR, a crystal, 2 caps and a resistor
with the arduino bootloader programmed into it. Easily obtainable from
several sources for 5 bucks or so. All the code, toolchain etc. (the
ecosystem as it were) is free. it's real easy to put one together on a
piece
of perfboard. If you're gonna put the phase detector, dividers etc.
together
anyway there's really no need to clutter things up with some ginormous
commercial arduino board.
Dale
-----Original Message-----
From: Keenan Tims
Sent: Thursday, December 06, 2012 10:38 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSDO Alternatives
As a lurker, I just want to chime in and say that I for one would love
to see an open-source GPSDO implementation. There are quite a few open
hardware designs out there, but as Bob suggests, all the interesting
bits are tied up in the closed-source software they run. And most of
them are no longer maintained, meaning it's getting hard to find parts.
I've thought on designing a hardware platform to support a GPSDO as
well, but don't have the time-nut or control theory skills (or
equipment) necessary to make the software any good. My hope at the time
was that a build it and they will come approach would solve those
problems, but I haven't had time to make that gamble.
As far as uP choice, Arduino's only saving grace is the pool of existing
'developers' in the amateur community for it - but that's perhaps a big
deal here. It's expensive, doesn't include debug hardware, and is slow
with not many peripherals. I'd second the STM32 ARM Cortex platform, or
suggest MSP430 if you want to stay cheap and slow.
Keenan
VE7XEN
On 2012-12-06 1:28 AM, Chris Albertson wrote:
On Wed, Dec 5, 2012 at 2:50 PM, <saidj...@aol.com> wrote:
If there is one thing I learned, it is that one is never finished
improving
the software. That is why we are time-nuts I guess.
This is the reason I suggested using the Arduino. It is so easy to
program
that MANY people will be able to contribute. That is my goal, a GPSDO
that
can be a "living project" that is not dependent on one or a few experts.
I'd like to see a budget of well under $100, again so that more people
can
contribute and experiment.
A design that can evolve will have just about any performance people
want.
So don't worry about if it is 1E-12 or 1E-15. Just make it transparent
and easy to understand and modify.
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