19 Jun
2007
19 Jun
'07
1:06 p.m.
..flipping through IC Master '81:
- The 74S481 4-bit slice.
- Fairchild CMOS 470x series (4705 4-bit ALU/register slice).
- Motorola ECL MC10800 series (4-bit ALU slice)
- Siemens ECL SH100B480 4-bit slice
Philips made a 4-bit wide slice ASIC called 'SPALU' (Scratch Pad +
Arithmetic Logic Unit -- 'scratch pad' meaning general purpose
registers). AFAIK it could only be used to make a 16 bit processor (I
think all 16 bits went ito each slice, but each slice only outputted 4
result bits). and was used only (?) in the P851 machine. It may not
really count, but it's a curiousity.
A weird chip I ran across recently in an early
80's protocol analyser is the
AMD 29116. The overview in IC Master calls it a
"16-bit Bipolar Microprocessor" but it only contains the ALU, registers, and
instruction register/decoding. It appears the program counter/sequencing have
to be provided externally, and it doesn't appear to be cascadeable so you
can't really call it a bit-slice.
AFAIk you can't casecade them (things like the carry signals are not
available externally in the right form, etc). The PERQ 3a (AGW3300) has a
pair of them on the CPU board for the graphics processor, according to
the schemaitcs one does the actual data updating, the other calculates
the addresse to be updatate. There an external control store (I forget
how big) with a simple counter as a sequencer (it can be loaded for
jumps, but there's no subroutine stack or anything like that). Obviously
you could use a more advanced sequencer, like a 2910 or something
-tony