Re: gEDA-user: Tag-Connect TC2030-MCP(NL) footprint, expert review

[Bob Paddock <bob.paddock@xxxxxxxxx>]

> On another note, have any of you used spring-pin connectors for
> programming/debug connectors to save space and BOM cost?  I have been
> thinking about how I would design my own spring-pin programming

We use Mill-Max 821/823 series to do AVR ISP program at work.
I can get you the exact number when I get back to the office on Monday.

Our jig kind of looks like a mini-sewing machine.  Lever press the six
pin connector into the holes on the board.

The levers are a standard "hold down clamps" from McMaster Carr:

http://www.mcmaster.com/#hold-down-toggle-clamps/=dld9w1

We also build Bed-Of-Nail spring-probe test fixtures out of blocks of
hard wax, and mill the holes for individual spring probes
to hit test points on the boards.  Same Hold-Down-Clamps are used here as well.

Every switch point, power supply connector, etc. has a test point pad
that hits a probe, for our board testers.

Something I've wanted to do Real Soon Now is make a universal board
tester out of a Actel Fusion FPGA (Have embedded ARM cores, A/D, D/A,
I/O etc),
were I load a program for the board and hook up one of the above
bed-of-nails for the target under test, rather than building testers
for each product.
A mini-version of the old Wayne Kerr board testers I use to work on.
Same fixture would be used to program the target as it is tested.
Typically a test a bootloader and a self-test program is loaded into
the micro during board testing.  A real application will get loaded,
via bootloader, on the production floor before final shipment.

Something from my blog:

http://blog.designer-iii.com/avr_isp_spi/20081116-10511-Digital-MEMS-Accelerometers-will-not-work-with-AVR-ISP-using-SPI

"You are supposed to isolated the AVR ISP pins with 1k resistors, as
the Atmel documentation shows".
  This is true. However that takes four resistors per board, on a
board that already did not have enough space. Also at 50,000 units per
year, with an design lifetime of five years, that is 1,000,000
resistors. After a while these resistors start to add  up to real
money, for what is a single event at manufacturing time. Design for
Manufacturing always should be given consideration.


I'll show people your T-C parts next week, might save us some room too, thanks.


-- 
http://blog.softwaresafety.net/
http://www.designer-iii.com/
http://www.wearablesmartsensors.com/


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