[time-nuts] TAPR TADD-2 PIC frequency divider

Magnus Danielson magnus at rubidium.dyndns.org
Sat May 23 12:53:43 UTC 2009


John,

Just a few friendly pointers.

John Ackermann N8UR skrev:
> The code is available at http://www.tapr.org/~n8ur/PIC_Code in both 
> source and object form.

Would you be so kind to provide a link from
http://www.tapr.org/kits_tadd-2.html (sixth paragraph discusses code) to 
http://www.tapr.org/~n8ur/PIC_Code ?

That way these types of questions does not have to re-occur again.

Similarly, a small README file could give the useful information below 
and be edited if and when additional versions is included.

That way people will quickly find the right information without the need 
to dig the time-nuts archives or google beyond the TAPR TADD-2 page.

Cheers,
Magnus

>  The "03-2009" version is what is shipping on 
> the current TADD-2s.
> 
> The "04-2009" version is a slight update from Richard McCorkle that 
> changes the way the ARM and SYNC LEDs work, and also allows selecting a 
> 50% duty cycle output (instead of 20%) as a compile time option. 
> Otherwise there are no changes (ie, no bug fixes).
> 
> John
> ----
> 
> Samuel D. [x86/CPC] said the following on 05/22/2009 07:38 PM:
>> Another question about the TADD-2 PIC divider : they said on main page 
>> the
>> source code for the pic will be released in open source. Does anyone 
>> know if
>> the code is available somewhere ?
>>
>>
>> -----Message d'origine-----
>> De : time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] De la
>> part de Magnus Danielson
>> Envoyé : samedi 23 mai 2009 01:33
>> À : Discussion of precise time and frequency measurement
>> Objet : [time-nuts] TAPR TADD-2 PIC frequency divider
>>
>> Fellow Time-nuts,
>>
>> I acquired myself two TAPR TADD-2 PIC frequency dividers as soon as 
>> they hit the list as orderable. Tonight I had the pleasure of 
>> completing the first one.
>>
>> For a beginner, this kit should be fairly simple. You need to have 
>> some ability to solder and read resistor and capacitors, even if most 
>> capacitors comes in separate bags (pretty neat brown bags, but hard to 
>> open without ripping the lid partly off). The manual could give better 
>> hints for the beginner, but it is nothing major at all.
>>
>> Since I fail to fall into the beginner group, I must say that it was 
>> pretty straight forward to build it. The double-sided, silkscreened 
>> and plated hole PCB made this as simple as any other modern kit and it 
>> is easy to make the mounting look good. I was supprised how well my 
>> resistor-leg bending was still up to speed and accuracy as they all 
>> went in quickly and smoothly. Everything went very smoothly.
>>
>> So, at last... everything mounted and time to power up. Without input 
>> it sits there quitetly. I hooked it up to the time-base output of my 
>> SR-620 and it kicked alive directly. 10 kHz, 1 kHz, 100 Hz, 10 Hz, 1 
>> Hz and PPS all just ticked away as expected. I hooked over to a 5 MHz 
>> source, the OCXO (TOYO oscillator of unknown specs) from an Ericsson 
>> AXE-10 station that I keep heated at the labbench with a BNC hanging 
>> free, and sure enought everything was half-rate including the PPS LED 
>> (very useful), but just unplugging the 5/10MHz jumper fixed that quick 
>> enought.
>>
>> A few items of criticism is in place, from a practical point of view. 
>> The TADD-2 does not perfectly match the TAPR TADD-series box. I was 
>> able to sneak out the PPS through the DC input hole, and the ARM and 
>> SYNC LEDS is way in there, so a similar approach was not possible. The 
>> 5/10 MHz jumper should possibly be made into a toggle-switch. None of 
>> those fits the casing, but using one of the DB9 holes should fit it 
>> nicely. The other DB9 hole could be fitted with a suitable DB9 
>> connector for power. None of these things is a show-stopper, but of 
>> mild details which could have been made better and very simple hacks 
>> will allow for a more versatile setup, for those wishing to use their 
>> TADD-2 as a lab-device, where as for fixed setups it is of close to no 
>> consequence.
>>
>> I only made a quick attempt to measure jitter, but it is way down 
>> there around ps or so. It was just an indicator measurement anyway. I 
>> will make some more propper measurements and analysis.
>>
>> Regardless, I think it is a nice kit and should allow for easy 
>> lab-ability for most time-nuts. I particularly like the simultanous 
>> outputs which is jumperable to suitable outputs and the 5/10 MHz 
>> jumper. The PPS LED allows for a quick view and the ARM/SYNC should 
>> allow for synchronisation. It fairly well fills a gap in my set of 
>> gear and should do that for others too. Doing picket fence exercises 
>> becomes trivial with one of these.
>>
>> Good work John, Tom and others that feel involved.
>>
>> Cheers,
>> Magnus
>>
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