Solved: Chicken-Egg-Problem with AVR DIY-Programmer
There are several projects to build an AVR-Programmer. But they all have the same problem.
How to program an AVR-Microcontroller without a Programmer. What can You do? For example use
your Sound Card to solve this issue.
We want to build the USBtiny Programmer from
http://dicks.home.xs4all.nl/avr/usbtiny/index.html
Wiring
The parts required are readily available and the circuit is easy to build.
Uploading the firmware
Connect your circuit to the headphone jack, turn volume up to 100%, activate the reset and press the play button.
A successful transfer is indicated by a blinking led.
There is no blinking!?
Ok you can try one of the following programming circuits.
In rare cases the signal produced by the sound card is inverted. (also by the second alternative circuit)
Download the .hex and use the hex2wav converter.
Change the fuses
The USBtiny Programmer is running with a 12 MHz crystal. We have to change the fuses. Repeat the steps above an press play.
(you cannot program the controller anymore; do this only after a successfull firmware transfer)
Links: