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Grogster

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Joined: 31/12/2012
Location: New Zealand
Posts: 9643

Posted: 05:24pm 18 Dec 2015

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Hi folks.

With Robert's permission, I post this thread for a simple PCB for his ascii ICSP unit.

Note that I have not yet fitted the zener on the bottom, nor finished soldering the pins, but Robert has confirmed that everything works as it should. Note also that I have forgotten to push the pin-header pins through for the jumper on 5v-RST-GND pins, but next time......

Using Shenzhen2U's 100x100 service, you can get 100 of these PCB's for US$11.90, or 12c each!(ten panels of ten boards per panel)

With this PCB, the extra parts to go on it, and a Nano module, the entire programmer can be built for about US$5.

The 6p header strip can be had in lots of 20 for US$1.26 from eBay.
Here is the link.

The Arduino Nano is easy to find on eBay - just search for it, as there are many traders selling the module. Usual price is about US$2.50 per module including pin-strips.

Here is the ZIP file with the overlays and Gerbers, so anyone who wants to, can get their own boards made.

ZIP file with images, overlays and Gerbers
Edited by Grogster 2015-12-20

Smoke makes things work. When the smoke gets out, it stops!

HankR
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Joined: 02/01/2015
Location: United States
Posts: 209

Posted: 05:43pm 18 Dec 2015

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G,

Are you sticking to your previously announced plan to do a full (or nearly full) kit for this fantastic little innovative programmer from Rob and his collaborator?

I'm thinking that because of that very low total price you might have decided to handle it this way. Either way, thanks for the slick, neat design.

Hank

Grogster

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Posted: 09:25pm 18 Dec 2015

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Hey there.

There is no money in selling a kit for US$5 or so, unless you can sell half a million of them or something, so I most likely WON'T be offering a kit - hence the ZIP file with everything you need to know to build them yourself.

I do still have 8 panels of boards(one panel I sent to Robert), so if anyone wants to buy panels, I can send a panel of ten boards anywhere on the planet for US$7.50 - airmail postage included.

I am happy to support the cause though, but the cheapest possible method is to get your own PCB's made from the supplied Gerbers, and assemble them yourself. To sell them as a kit with the module, my price would have to go up to around US$20 to make it profitable for me - I am, after-all, running a business.

Having said that, I therefore think it is in everyone's best interests that I just release the design and Gerbers, and people can then get their own batch of boards done, ensuring that the programmer is indeed kept to the US$5 price-tag, and that is a good thing.

It could make a nice wee classroom project for students - assemble the programmer, and then use it to program the MM firmware, then use the MM in class.

Smoke makes things work. When the smoke gets out, it stops!

BobD

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Joined: 07/12/2011
Location: Australia
Posts: 935

Posted: 09:43pm 18 Dec 2015

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This looks like a great little gadget. However, beware if the price of building it starts to ramp up. It is possible to buy Pickit 3 clones from eBay Hong Kong for as little as US$12 and this includes postage and all cables.Edited by BobD 2015-12-20

Grogster

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Posted: 09:46pm 18 Dec 2015

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Exactly why I am not bothering to offer a kit for this one.

Building your own one of these is certainly the cheapest way to do it.

Smoke makes things work. When the smoke gets out, it stops!

Grogster

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Posted: 12:13am 23 Dec 2015

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Well, finally got around to fitting the elusive 3v3 zener(cos I did not have any till today!), and can report that the programmer goes fine, and I was actually surprised - it was faster then I thought by about 20 seconds.

Rob - any idea why that would be?

....not that I am complaining....

Smoke makes things work. When the smoke gets out, it stops!

robert.rozee
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Joined: 31/12/2012
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Posts: 2447

Posted: 03:09pm 23 Dec 2015

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my feeling is that there is a great deal of 'idle' time spent in the USB drivers waiting for traffic to be sent and acknowledged. bearing in mind that the pathway consists of:
windows serial API -> USB drivers -> USB transport -> bridge to serial

the USB hardware is geared to either very small quantities of intermittent data (keyboard, mouse, etc) or very large blocks of data (disk drive). whereas pic32prog is throwing at it a vast stream of very small packets that the serial API is mixing up in who-knows-what-way. profiling the code reveals that pic32prog spends about 2 seconds processing data, with the remainder of the run time blocked by the serial API.

cheers,
rob :-)

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