Arhive categorie: ATtiny85

USBTinyISP using ATTiny85

Some time ago I’ve found a project of an USB programmer that used an ATTiny85 microcontroller to emulate all the functions of a FTDI programmer. The reason I wanted to build this programmer was mainly the cost and availability of the parts. I had some ATTinys laying around, but the problem were those two 3.6V Zener diodes that are not commonly available everywhere so I’ve managed to buy some sort of Zener diodes kit from banggood, and it was nice to found that certain value in the kit. However, Zener diodes are kind of optional and if you search about this subject you can easily find people reporting that the widely used 1N148 diodes connected in series are useful to drop the voltage to certain levels if Zener diodes are unavailable.
Anyways, the inspiration came from this site. I’ve used the drawn schematic to make my own in Cadsoft Eagle.

This is the original schematic…

And this is the schematic made by myself…

Schematic USBtinyISP

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