The 1750W

The MIL-STD-1750A is a 16-bit design that can address up to 64K words of data and 64K words of instructions. Using a memory management unit, it can address up to 1M words of instructions.

We consider extending this to 32 bits to address up to 4G Bytes of memory.

We propose the 1750W, which has 32-bit registers and a 32-bit mode. In its start-up mode it runs exactly as a 1750A, except for one additional XIO command that switches it to 32-bit mode.In 32-bit mode the 1750W is still word-addressed and has a 16-bit data bus. The address bus is wider and can be as wide as 32 bits. More likely it will be 24 bits wide to allow up to 16M words of code and data.

Why not just use a 32-bit computer?

The 1750 is a simple design and is available as a space-qualified part. The 1750 is space-proven and generally considered to be a low risk choice. The extension to 32 bits will retain these benefits.

We are considering the details of how this would work, and what impact it would have on the compilers.

If you are interested in a wider 1750, please let us know.