AVR Programmer (old)

A better design was found, that is what I use now.

I am designing a circuit board for a simple stk200 style programmer that will work with the uisp programming software for Linux. This programmer will work with most 8, 20 or 40 pin AVR chips.

Schematic Component Layout
Schematic Component Layout
6-pin ISP Header 10-pin ISP Header
x Gnd


November 9, 2005
Breadboarded and tested the circuit

Breadboarded circuit Note that there is an exta IC in the picture. I did not have a 244 on hand so I used to 245 and a 4049 (inverter) to make a 244.

November 19, 2005
Built circuit inside small project box.

Note: My cable from the PC is rather long so I added a 0.1uF capacitor between Vcc and Gnd on the 244. I also observed that with the LED driven directly from pins 12/14 I would get flash verify errors. Adding a transistor drive eliminated this problem.

December 23, 2005
I have seen some problems with this programmer. Uploading flash caused 2 ATMega16’s and an ATTiny26 to stop responding. I was able to revive the ATTiny26 by hooking the calibration output of my scope to XTAL1 and using a dasa style programmer to erase the chip. The ATMega16’s are still quite dead. I think the issue is the length of my cable.

The dasa style programming cable uses 4 wires from the serial port (RESET=RTS SCK=DTR MOSI=TXD MISO=CTS). Like many others on the internet I have to manually reset the chip between operations. I leave the RTS line unhooked and just use 3 of the 4 wires.

December 31, 2005
I was able to revive the ATMega16’s by applying a 1MHz clock signal to the XTAL1 pin and resetting the fuse bits to default with my serial programmer. The clock signal was generated with another AVR running a simple pin toggling infinite loop.