Motorola 6800A {microprocessor} released shortly after the {Intel 8080}, in about 1975. It had 78 instructions, including the undocumented HCF ({Halt and Catch Fire}) bus test instruction. The 6800 evolved into the {Motorola 6801} and 6803. The {6502} was based on the design of the 6800 but had one less data register and one more index register. (1994-10-31)