An attiny2313 usb2gpio adapter FAIL

They say on they’re running out of fails for their weekly fail series. So I decided to help them out a little bit 😉
Anyway, a few weeks ago I needed a few usb-to-gpio modules to drive switch some basic stuff on and off from an MK802 dongle. Usually I take an attiny2313 and etch a board for this purpose, but this time I was short on free time to do it myself.
The schematics are well-tested a long time ago. vusb powered firmware based on antares and lunartool applet for the host side are also ready and fully debugged. What could possibly go wrong in such a damn simple project?

However this time boards (already tested multiple times when etched at home) were a failure. Mostly because I was in a terrible hurry to reroute them, replace 2.54 pins with screw terminals, add mounting holes and send them to the fab…


Here are some more photos.


IMG_20131223_184404 IMG_20131223_184432

And a list of fails, if you haven’t guessed yet:

  • SCK/MISO/MOSI on the silkscreen are way off the real SCK/MISO/MOSI
  • mini-usb slot is positioned in a way no cable would fit it. Had to give each board a cut to fix that.
  • I screwed up making the 14-pin screw terminal footprint: the drill holes were too small, so I ended up with the hackery shown above.

Apart from that – the design was fully operational. If somebody wants the firmware sources for that – leave it in the comments, and I’ll put it up.

Note to self: Never trace PCBs while in a hurry.


4 thoughts on “An attiny2313 usb2gpio adapter FAIL

  1. Интересная привычка – на подтяжку ресета постоянно вешать выводной 10к-резистор 🙂 Экономия нервов при разводке платы?

  2. Нет, все намного прозаичнее. Когда только начинал этим безобразием заниматься закупил овер9к^W 1000 штук выводных. Ну или около того. Почесав голову позже решил лепить по одному на каждый проект. Глядишь к пенсии закончатся 😉

  3. второпях разводить, а потом китайцам отправлять на изготовление? и ждать почту россии? (или это всё не в рф?)
    а на мк802 стандартный андроид, или что-то иное? увидеть бы весь сетап в деле..

    1. А на MK802 кто-то НЕ сносит андроед? o_O
      Разумеется там debian armhf.
      А сетап пока еще не закончен, там еще целую полку собирать, веб морду пейсать и т.п.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.