Test clips for 32-TQFP package?

[zapta]

Are there in circuit test clips for 32-TQFP packages? For example something like this one

http://www.warwickts.com/5733--pomona-32pin-plcc-test-clip-p545

I am designing a PCB for with a atmega328P avr and would like to avoid the ICSP header area.

[jeremy]

Plenty: http://www.aliexpress.com/wholesale?SearchText=qfp+32+socket&opensearch=true

[rolycat]

Plenty: http://www.aliexpress.com/wholesale?SearchText=qfp+32+socket&opensearch=true

Those are sockets designed for loose chips, not in-circuit testing.

I think zapta is looking for something like this.  CLIP-032-QF59-4 is a snip at $719.48. Not in stock at the moment, though.

[Rerouter]

why not just leave pads and pogo pin to program? just as i cannot see that being any harder than wiring up a qfp32 test jig

[Dago]

why not just leave pads and pogo pin to program? just as i cannot see that being any harder than wiring up a qfp32 test jig

Or use some smaller connector for programming (like 1.27mm pitch pinheader for example) and use a custom programming cable if space is an issue (I kinda doubt it since you're using a TQFP packaged MCU).

[jeremy]

Plenty: http://www.aliexpress.com/wholesale?SearchText=qfp+32+socket&opensearch=true

Those are sockets designed for loose chips, not in-circuit testing.

I think zapta is looking for something like this.  CLIP-032-QF59-4 is a snip at $719.48. Not in stock at the moment, though.

Ah my mistake, sorry. Did not read closely enough.

Alternative: have you thought of using bootloaders instead? You can boot off SPI, I2C, UART, SD card, whatever you like! Assuming you already have some IO, it means you don't need to add anything to the PCB. You can also put headers on a side-board which can easily be cut off from the main board.

[Circuitous]

I too could use similar clips for a couple of packages, but haven't found quite the right sizes.

Alternative: have you thought of using bootloaders instead? You can boot off SPI, I2C, UART, SD card, whatever you like! Assuming you already have some IO, it means you don't need to add anything to the PCB. You can also put headers on a side-board which can easily be cut off from the main board.

I'm curious, how are bootloaders relevant in any way to the OP question?

[hlavac]

I'm curious, how are bootloaders relevant in any way to the OP question?

Quite. Microcontroller manufacturers provide preprogrammed chips service.
If you have some sort of external I/O you could use it with a bootloader to program the firmware in system by having the bootloader preprogrammed.
Some chips with USB hardware (ATmega32U4 for example) come with USB bootloader by default!

[Circuitous]

If you have some sort of external I/O you could use it with a bootloader to program the firmware in system by having the bootloader preprogrammed.
Some chips with USB hardware (ATmega32U4 for example) come with USB bootloader by default!

I know what a bootloader is, how it works, and why I might use it for a project.

But, once again, how is even the concept of a bootloader relevant to the search for TQFP clips?

Many, if not most embedded applications, don't use bootloaders (Arduino weenies excluded).  Even if a bootloader is used, that doesn't change the need to probe the chip.

Back to the OP question, any sources or recommendations for TQFP clips?

[hlavac]

OP wants to use the clip to program the microcontroller connecting the ISP lines to it thru the socket instead of the dedicated ISP connector footprint he wants to avoid.
Just suggesting cheaper ways to do it

[FrankBuss]

If you don't need it to optimize for fast production, you could use some of these SMD grabbers:

http://www.digikey.com/product-detail/en/72902-0/501-1172-ND/1196307

Works down to a pitch of 0.5 mm. Another idea is to use pogo pins and a programming jig:

http://www.adafruit.com/blog/2010/06/10/how-to-make-a-pogo-pin-testing-jig/

Instead of holes, you could place the ISP connection on the bottom side of the PCB, under the chip, as SMD pads. There are all kind of different pogo pins for this kind applications.

[attie]

I think this is what you're after?

http://www.hobbyking.com/hobbyking/store/__27195__atmel_atmega_socket_firmware_flashing_tool.html

[hlavac]

Wow, great find attie $19.99

[attie]

If you're designing the board, rather than performing a bit of reverse engineering, then there also these guys: http://www.tag-connect.com/
Awesome concept, and I've had good results (generally try to use the 'with legs' variants for reliability of connection - otherwise you have to hold the pogo pins down).

[zapta]

Great information. Thanks everybody. I will start with the Hobby Kind adapter (just placed an order), will hook it to my AVRISP MKII (may need to adapt the wiring). The Pomona micro grabber is also very interesting, I think I will get one for testing purposes and see how well it will work.  The tag connect is a good option for a small footprint adapter, e.g. to connect to a boot loader. The legless version takes little space and seems to be better centered than common pogo arrangements (e.g. https://www.sparkfun.com/products/11591) and are available for sale at Microchip, will keep it bookmarked.

[codeboy2k]

If I'm space tight, I've also done fingers at the edge of a board and used pogo pins or a clip-on clamp for programming.
I almost never want to put a 0.1" header on anything these days unless the board is extra roomy like a big sedan

But almost always there is no good reason to waste real-estate on a programming header anymore.


 

[zapta]

If I'm space tight, I've also done fingers at the edge of a board and used pogo pins or a clip-on clamp for programming.
I almost never want to put a 0.1" header on anything these days unless the board is extra roomy like a big sedan

But almost always there is no good reason to waste real-estate on a programming header anymore.

What kind of clip-on clamp?

[codeboy2k]

If I'm space tight, I've also done fingers at the edge of a board and used pogo pins or a clip-on clamp for programming.
I almost never want to put a 0.1" header on anything these days unless the board is extra roomy like a big sedan

But almost always there is no good reason to waste real-estate on a programming header anymore.

What kind of clip-on clamp?

A big plastic clothes pin seriously.  Nothing professionally available, so I made it up.  Make the target PCB with fingers near one edge, spaced  0.1" apart, then make a clothespin with a 0.1" header in its jaws , using the the bottom side (small pins) to clamp onto the PCB and "bite" into the fingers, and the longer side of the header for soldering wire to. It's really quick to clamp onto a board for a quick ICSP download when producing a dozen or so boards.

I did it at a company lab I was at before so I don't have this here, but it was similar to this one:

[dannyf]

would like to avoid the ICSP header area.

How about discrete, individually placed pins on the pcb? How about another atmega with programming algorithm + the hex file? Piggy-back it onto the target - the pins are perfectly aligned - and power it up. The atmega on top will then program the target underneath it.

Or a bootloader for a total software solution.

[free_electron]

Tagconnect. Put on the backside of the board.

[zapta]

Tagconnect. Put on the backside of the board.

It's very nice, especially the no-leg version, but expensive, $47 shipped.  I am designing open hardware and trying to minimize the cost of the requirements.

[alank2]

I know this is an old thread, but I made up an inline isp 50 mil connector for small pcb's.  I can often fit this under an ic like an attiny1634 for example.  No need for pogo or springs, just make small through holes and put the pins in and hold at a slight angle to make contact.  I think I ordered like 9 of these pcb's from oshpark for 74 cents delivered.  You'll probably have to buy some single row 50mil header to break apart too.

[zapta]

I ordered recently pogo pins from eBay and they are inexpensive and work well, a few bucks for a bag of 50. If you want the to fit in standard header holes, pick the ones with 1.02mm at the soldering end.

You are right, OSHPARK is a steal for small boards.

[alank2]

If anyone wants to use what I am calling mini isp (50mil inline isp), here are the gerbers and info:

cost to implement on a pcb ($0)
  40 mil pad diameter
  24 mil hole drill
  50 mil spacing

Example of putting this isp header on the other side of a tiny1634:



some 50mil header (you can make 8 2x3 100mil to 1x6 adapters with this):
  S9014E-50-ND $3.60 @ digikey

60 cents for 3 pcb's at oshpark (including shipping!)

gerbers:
http://home.earthlink.net/~alank2/mini_isp.zip

Good luck,

Alan