Help with simplified avr isp programer

[dfox]

I have made the programmer and can only seem to be able to write the fuses i.e clk 0,1,3. But cannot seem to be able to write the hex, always says writing failed after finished. Does the programmer need addtional power source to program the atmega8 ?

I am confused asmto the wire to the Atmega from the parallel port, any help would be most appreacited.

Many thanks

[Herman]

Yes you requires an external 3.3/5v supply to program the chips properly.  I think you can sometimes use the other parallel lines with diodes to create the voltage source but i have found that problematic in the past and now use an external source without issues.  If you do use an external voltage source, make sure you connect gnd to the rest of gnd else it wont work

[dfox]

Ended up using a usb cable which was quick, thanks again for all your help