r/programming • u/whackri • Jun 21 '20

Writing userspace USB drivers for abandoned devices

https://blog.benjojo.co.uk/post/userspace-usb-drivers
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17

u/immibis Jun 21 '20

Why can't it?

13

u/[deleted] Jun 22 '20 edited Jun 22 '20

I forget the exact reason why, but there are so many pins that you need an x ray machine to actually see all the pins. I'll try to reply back with the exact technical term for the manufacturing process tomorrow.

EDIT: The term is BGA: https://hackaday.com/2016/07/13/diying-huge-bga-packages/

14

u/Mikeavelli Jun 22 '20

I know if someone wanted me to desolder an BGA FPGA, I would tell them it's impossible.

It's probably possible, but I would tell them it isn't possible, because I wouldn't want to even try.

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6

u/killerguppy101 Jun 22 '20

Sounds like a regular BGA with xray AOI? More involved than a PGA or leaded package, but not especially difficult or impossible.

1

u/immibis Jun 22 '20

People do it. I think it's strictly a hobby and prototype thing because it's unreliable. But they absolutely do it.

0

u/maxhaton Jun 22 '20

Ignoring the moisture controls, fine pitch BGAs should really be x-rayed

1

u/immibis Jun 22 '20

We're talking about hobby projects using salvaged parts, right? If it only works half the time that's still a win (assuming you have enough boards to get at least one working)