[time-nuts] ARM boards for low-cost GPSDOs

paul swed paulswedb at gmail.com
Fri Apr 11 10:16:33 EDT 2014


David we may be drifting from Hals thread. So don't want to do that.
I looked at the system and its governed by the xtal they use. Granted its
cheap and totally in an uncontrolled environment. Mine typically is +.79
ppm at 1 Mhz. Semi consistent. Its really easy to bypass that xtal and to
inject some higher quality source and reap those benefits. They have little
pads and such to allow it.
Regards
Paul
WB8TSL


On Fri, Apr 11, 2014 at 7:49 AM, davidh <dhooke at gmail.com> wrote:

>
>
> Hi All,
>
> I've used the STM32F4 for a few projects, and was considering it for a
> time tagger for a DMTD system. I have a question about the clocking though
> that someone may be able to help me with.
>
> The 32F4 (like lots of similar ARMs) uses a PLL to generate the internal
> clocks from much lower frequency clock or crystal. Has anyone quantified
> the stability of the synthesised clock?
>
> Thanks,
>
> david
>
>
>
> On 11/04/2014 8:02 AM, Alberto di Bene wrote:
>
>> On 4/10/2014 11:38 PM, Hal Murray wrote:
>>
>>  Does anybody have a favorite low-cost ARM board?  I'm looking for a
>>> simple
>>> Arduino like setup rather than something that runs Linux.  The idea is
>>> to get
>>> 32 bit counters so a bunch of the recent discussion can be ingnored.
>>>
>>
>> ==========
>>
>> I can't recommend warmly enough the Discovery board from STM.
>> It sports a Cortex ARM M4F that can run at 180 MHz, has a native
>> IEEE compliant floating point core, 2MB flash and 256 kB RAM,
>> and a wealth of interesting peripherals on chip, TFT display touch
>> enabled included.  And at 23.52 USD is cheaper than a much
>> less powerful Arduino...
>>
>> I implemented on it a fully featured SDR, without using any opsys,
>> talking directly to the bare metal using the Keil IDE/compiler.
>> A joy to use. Look here :
>>
>> http://www.st.com/web/catalog/tools/FM116/SC959/SS1532/LN1848/PF259090
>>
>> 73  Alberto  I2PHD
>>
>>
>>
>>
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>
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