The BlinkyIRQ example is not compatible with the Atmel AT91 family. And none of Atmel's appnotes use GNU. Is it possible to use the same: void tc2_test (void) __attribute__ ((interrupt)); // Generate Interrupt setup for the AT91, or is it necessary to use the assembler handler examples that Atmel gives in their application notes? Any other comments of suggestions would be appreciated. Thanks, Al