Motorola 6809

Motorola 6809

General information
Launched	1978; 46 years ago (1978)
Common manufacturer	Motorola
Performance
Data width	8
Address width	16
Architecture and classification
Instruction set	6809
Number of instructions	59
Physical specifications
Transistors	9,000
Package	40-pin DIP

The Motorola 6809 ("sixty-eight-oh-nine") is an 8-bit microprocessor with some 16-bit features. It was designed by Motorola's Terry Ritter and Joel Boney and introduced in 1978. Although source compatible with the earlier Motorola 6800, the 6809 offered significant improvements over it and 8-bit contemporaries like the MOS Technology 6502, including a hardware multiplication instruction, 16-bit arithmetic, system and user stack registers allowing re-entrant code, improved interrupts, position-independent code, and an orthogonal instruction set architecture with a comprehensive set of addressing modes.

The 6809 was among the most powerful (and most expensive) 8-bit processors of its era. In 1981 a 6809 in single-unit quantities was $37 compared to $9 for a Zilog Z80 and $6 for a 6502.^[1] It was launched when a new generation of 16-bit processors were coming to market, like the Intel 8086, and 32-bit designs were on the horizon, including Motorola's own 68000. It was not feature competitive with newer designs and not price competitive with older ones.