AMI > AMI68A09
Modified: March 15, 2005, 10:10 pm
Data Code:8515
Process:3 Micron
Architecture:8 bit
Used in:Control applications and Computers
Description:Enhanced version of the 6800 8-bit
microprocessor, Motorola 6809 added many new

New instructions for loading effective address
into registers and exchanging the contents of

New stack handling instructions, including
instructions for saving and retrieving the
contents of one or more registers to/from the
stack. In addition to the system stack pointer
the 6809 includes additional user stack pointer.

New Direct Page register was added to enhance
direct addressing mode.

Indexed addressing of the 6809 was expanded to
provide new addressing modes: indexed addressing
using one of 4 registers (2 stack points, X index
register or new Y index register) with 5-bit, 8-
bit or 16-bit offset, indexed with accumulator
offset, indexed with auto-increment or auto-
decrement by 1 or 2, and relative to program
counter addressing.

16-bit relative branches could be used to build
larger position-independent programs.

16-bit data processing.

The Motorola 6809 was produced in two versions -
with on-chip clock (6809) and with external clock
input (6809E).

There were many second sources.