31 Dec
2005
31 Dec
'05
3:33 p.m.
Is there some really interesting documentation
available for these
chips and maybe some microcode for some really simple task? I'd like
to really understand how bit-slice CPUs do work to form something like
a VAX CPU.
Remember the 2901 is just the ALU, 16 4-bit registers, and the associated
interconnection circuity (multiplexers, etc). If you understand how those
work, understnad propagate/generate carry, and know how to make a
microcoded CPU in general, then there is little more to learn for the 2901.
That said, there is a very good book on the 2900 series called 'Bit Slice
Microprocessor Design' by Mick and Brick (no, those names are not a
joke). It's not easy to find (or at least it took me some time to find
it), but it does contain several examples of 2900-based circuits with the
microcode.
-tony