Motorola 6800

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See Wikipedia for good technical and historical information and references on the Motorola 6800.


Chip Photos

We depackaged, deprocessed and photographed a later depletion-load version of the chip, which shows signs in the layout of the previous enhancement-load version. Ijor then captured polygons from the photos - here are JPEG images, which may be easier to explore than the svg format:

Medium size Full size (14Mbyte) The recaptured polygon data closely resembles the original layout which defined the masks used to manufacture the chip, and is a great deal easier to study than the photographs.

Chip Simulator

From the polygons we were able to construct a netlist, and Segher has labelled many of interior nodes, so we can present a have a JavaScript simulator: (graphical mode) (non-graphical mode)

Points of Interest

We've found these interesting features (more detail to be added)

  • register circuit using resistive feedback and enhancement-style pullups
  • data latch circuit using weak feedback transistor
  • clock pulse shaping
  • resistive bus pullup
  • Manchester carry chain

Block Diagram

Here's the block diagram from the 1976 topology patent (See also this later patent.): M6800-arch.png


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