As this thread wanders off topic this industry was introduced to a new mnemonic in Byte article about decoding the undocumented Motorola 6800 instructions. The HCF (Halt Catch Fire) opcode $DD or $D9. HFC locked up the processor and cycled the address bus The author of that article was Gerry Wheeler. Gerry Wheeler, 54, died October 15, 2006, advanced non-Hodgkins lymphoma cancer. Gerry made significant contributions to the technology of the embedded systems world and was a key part of the development of many household name products. Programmer, Ham KG4NBB, author, father, husband, active commuity participant Gerry will be missed by all. w..