I'm currently programming over an Atmega 168A micro controller through a USB Tiny programmer and an ISP interface.
The micro controller is set up with an external oscillator and an external person helped me by programming the corresponding fuses for its usage. The problem is I accidentally cleared the fuses and know avrdude can't communicate with the micro controller.
Every time I try to program I get the error:
avrdude: initialization failed, rc=-1
Double check connections and try again, or use -F to override
this check.
All connections are correct.
I'm working on a Mac where I installed Crosspack-AVR and an AVR plugin for Eclipse. How can I restore communication with the hardware?
Depends on that value you wrote to the fuses. If you disabled your external reset pin (RSTDISBL) or the serial programming interface (SPIEN) you only can use "high voltage" (high means 12V :-) programming. You may look for a capable programmer (eg. AVR dragon).
If you "just" screwed up the clock settings you can feed a clock signal to the XTAL1 pin and try to hook up your ISP programmer. You should increase the bit duration time to slow down the programming speed (i think it was the -B4 option)
If you set the lock bits you may trapped out yourself for ever.
If you program fuses always keep in mind, that a physical 0 means programmed and a 1 means unprogrammed. the tools are not consistent with this. some may show a checkmark if it is logically set (programmed = physically 0) some show the physical data.
If you use avr dude. i would recommend using AVR8 Burn-O-Mat that has a decent GUI for fuse settings of many AVR8 types.