The Pogo-Key — 1.27mm AVR ISP adapter take II

The key to successful AVR programming :->

IMGP8465

The previous version of this adapter had a major disadvantage – assembly was a mess. You needed a jig, sticky tape… not good.

This one is much better in that respect.

Pogo-pin alignment is facilitated by split extra-long pads on the circuit board. It still requires dexterity and patience, but there is no more guesswork involved. If the pins are pushed into the gap of the split pins, they will be straight.

Another advantage is better mechanical support for the pins. Less chance of accidentally snapping them off.

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6 Responses to The Pogo-Key — 1.27mm AVR ISP adapter take II

  1. Dan says:

    What’s your method of ensuring you don’t connect the “key” to your target board backwards? I’d hate to fry a chip because I reversed the programming cable… :-)

    • robert says:

      Ah! As with most low-cost programmers & cables, we have chosen to rely on proper silkscreen markings and the user’s ability to interpret these hints correctly.

      Registration pins would’ve been nice, but we developed this adapter with essentially no board-space to work with. It had to be as small as possible.

      You could get a tag-connect cable instead. Of course it costs a lot more.

      • Dan says:

        Oh, now that I’ve looked more closely, I see the pin 1 triangle on the 2.54mm connector silkscreen. Do you just match that with the square pad (pin 1) on the target board?

        • robert says:

          Yup, that’s the plan.

          On a bigger target board I would also have added a better indicator on the silkscreen.

          In this case I felt it would’ve made it look less “clean” and too cluttered. Board appearance was a big part of the project.

  2. Patrick says:

    I enjoy these because everybody seems to be moving in slightly different directions with header miniaturization. Because I was worried that fanning out 2×3 1.27mm headers might be too exciting, I went with a simple 6 pin 1.27mm SIP where MOSI, MISO and SCK are all in the right order for the target chip. The annular ring is pushing tolerances and I really expected them to be a big shorted mess when Seeed shipped my boards, but in practice it worked out nicely, although I haven’t determined the durability of the 1.27mm headers as mock pogopins yet.

    • robert says:

      Yes, the tracks in-between the 1.27mm pads are pushing the limits a bit, but it seems to have worked. As far as I can tell, the fab has altered the pad-shape a bit, so they could fabricate the boards.

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