April 26th, 2009 ~ by admin

CPU of the Day: A 2-bit slice of the past: 3002

Often times its easier, and cheaper to break a big job down into smaller more manageable chunks.  The same goes for processing, and back in the 70’s and 80’s was fairly common.  ‘Wider’ processors were available, but were expensive and often not very flexible.  Bit slice processors were invented to fix this. a BSP is essentially an ALU (Arithmetic Logic Unit) that was 2 or 4 bits wide.  They could be put in parallel though to make processors of any width you needed.  intructions and control would then be fed to them by a control/sequencer chip.  Perhaps the most famous was the AMD 2901, a 4 bit slice device which is still in production today by companies like Innovasic.

Signetics 3002 BSP

Signetics 3002 BSP

Intel also made a BSP, called the 3002. It was 2-bit slice processor and was second sourced by Signetics, as well as Intersil. Released in September of 1974, it was clocked at 6MHz, very fast for the time, and another reason BSP’s were so popular. Above is a Signetics made 3002 in an all white ceramic package. Fairly unusual in that the lid is also white.