Information on the PPS-4/1 4 bit microprocessor wanted

The early 70's LSI was mostly PMOS. Simpler devices were often a good match to a 9V battery in handheld devices where that was the target. You wouldn't believe how much effort was put into putting LED drivers on the same chip where they could (often they couldn't and the LED driver was off the main logic chip.) More complex PMOS logic often had special supplies for clock and enable lines. You often find small switching converters (magnetics or charge pump) to generate the required voltages. A little later high-density NMOS also would use oddball voltages (both positive and negative depending on application) for density's sake. e.g. 8080A. Some good examples of how some handheld devices generated the necessary oddball voltages at http://www.jacques-laporte.org/HP35%20power%20unit.htm Tim.