[time-nuts] GPSDO Alternatives

EWKehren at aol.com EWKehren at aol.com
Thu Dec 6 19:26:33 UTC 2012


How about quit talking and build something and show us some results!
Bert Kehren
 
 
In a message dated 12/6/2012 2:09:38 P.M. Eastern Standard Time,  
dale at nap-us.com writes:

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-bounces at febo.com [mailto:time-nuts-bounces at 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" <lists at 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-bounces at febo.com  [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Dale J.  Robertson
> Sent: Thursday, December 06, 2012 12:45 PM
> To:  time-nuts at 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 at 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, <SAIDJACK at 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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