|Word size|| 4 bit|
The PPS-25 (also PPS25; Programmed Processor System - 25 Digits) was a family of 4-bit multi-chip microprocessor developed by Fairchild and released in 1971/2. The PPS-25 was designed for scientific calculations. While there is no definitive starting production date available, there is evidence pointing to early 1971/2 (some early books placing it ahead of the 4004 at the second quarter of 1971). This family was very short-lived as within a few years, Fairchild shifted their effort toward more advanced designs such as their macrologic families 4700/9400 and what became their flagship product, the F8.
|Help! This article is about the Fairchild PPS-25 family that has lost in the mists of time. Please help use restore and preserve this info! If you have more information pertaining to this chip please consider editing this page or posting that info on its discussion page (e.g. datasheet, manuals, catalogs, or any other literature on the subject would be help greatly).|
The PPS-25, Programmed Processor System - 25 Digits, was a 4-bit microprocessor system intended for scientific calculations. The system was 25-digit (100-bit) seriel, 4-bit parallel operating at 62.5 µs word time and 2.5 µs bit time. That is, the addition of two word (25-digit each) took 62.5 µs with multiplication being 50 ms.
The system supported up to 26 ROMs, each consisting of 256 micro-instructions.
|3806||Control and timing unit|
- Jack Belzer, Albert G. Holzman, Allen Kent (Jul 1, 1978). Encyclopedia of Computer Science and Technology: Volume 10 - Linear and Matrix Algebra to Microorganisms: Computer-Assisted Identification. page 401
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