I´am working in a project with the atmel atmega8a MCU. I´ve designed a code that works with an external 16MHz crystal. For that reason i burn the atmega8a´s fuses with the AVRISPmkII programer (HIGH FUSE:C9 LOW FUSE:FF) for a external 16MHz crystal. I test the functionality of the system with a atmega8a PU and this works perfectly. Now i´m trying to do the same in a PCB with the atmega8a AU but the burn fuses process don´t work in the same way. After this process the atmega8a AU MCU doesn´t work again and the programer can´t recognize it.
It´s something different in the burn fuses process between the atmega8a PU and the atmega8a AU? anybody knows why happens this???
I hope you can help me with this trouble. I´ll been waiting your answer. Thanks a lot.
Take a fresh ATMEGA8 controller(1 MHZ internal default clock frquency). Now write a program just to make a PIN high and low without any delay. Such as pin 14 gives high low pulses. Then connect pin 14 to that ATMEGA8 controller which you are unable to reprogram .
Then see the magic.