encounters with electron•ics / by flabbergast

VUSBtiny AVR programmer

As an exercise in soldering (to which I’m quite new), I decided to take the VUSBtiny programmer on a breadboard and make one on a piece of a stripboard. I used a stripboard with 3x1 strips (so I didn’t have to etch anything off). The schematic is of course the same as the original breadboard version, except I added female headers for the USB and the ISP-out connection. Since I routed some wires underneath the ATtiny, instead of soldering the IC directly, I let it “stand” on a pair of precision female headers. Of course a dedicated socket is also fine (but I didn’t have one); I think one’d need a precision one, since there’s not much space underneath the usual one.

Here’s a Fritzing sketch with the diagrams: vusbtiny-strip.fzz. It looks pretty messy, but you can see that the result is not so bad :) The parts need to stand up, and one can wire a lot of connections using the leads of parts.

Since this was my first ISP programmer, I programmed the ATtiny45 using Arduino as ISP – I used my Uno R2 (with a 10uF capacitor between RESET and ground to prevent autoreset on the Uno).

One pretty important point is that one needs to set the fuses on the ATtiny in such a way that the RESET pin is disabled - the consequence being that the ATtiny can be no longer programmed using an ISP (only with a HVSP; this state can be described as a “bricked chip”, if you’ve got a wrong firmware on it), so make sure that the correct firmware (from the original breadboard version) is flashed before setting the fuses!

More pics: