M6800 Microprocessor Programming Manual

Motorola 6800 is a 8-bit microprocessor which was released at about the same time as Intel 8080. The 6800 had a 16-bit address bus and could address up to 64 KB of memory. From common registers the CPU had only two accumulators and one index register. The 6800 didn't have I/O instructions and therefore 6800-based systems had to use memory-mapped I/O for input/output capabilities. Motorola 6800 started the big family of 680x microcontrolers and microprocessors, some of which are still produced today.