 PPS-4/1 single-chip model | |
| General information | |
|---|---|
| Launched | 1972 |
| Discontinued | 1990s |
| Common manufacturer |
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| Performance | |
| Max. CPU clock rate | 256 kHz |
| Data width | 8 instruction, 4 data |
| Address width | 12 |
| Physical specifications | |
| Package |
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The Rockwell PPS-4, short for "Parallel Processing System, 4-bit", was an early 4-bit microprocessor from Rockwell International, released in late 1972. Although practically unknown today, the PPS series was widely used in calculators, games and toys, and other embedded applications. Updated versions continued to be produced into the 1980s.
The original version was implemented in a three-chip set, consisting of the CPU, a clock generator, and a user ROM. In 1975, the clock generator was integrated to produce the PPS-4/2 with a variety of ROM and RAM support chips. In 1976, the PPS-4/1 added user-customized ROM to produce a single-chip solution, running at a lower speed.
The release of the PPS-4/1 coincided with the release of the Rockwell PPS-8, an 8-bit version of the system. New support chips released for the PPS-8 also worked with the PPS-4/1. These later versions of the lineup continued to be produced into the 1980s. The PPS-8, however, was abandoned shortly after its introduction as more advanced 8-bit processors entered the market.
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