ZTPE website

This site describes the project to restore my ancient 2650-based computer that I call the "P1".

The 2650 microprocessor is an 8-bit microprocessor from Signetics from the late '70s and early '80s. Several companies sold boards using this processor, including Central Data. I obtained a modified copy of the Central Data board in 1980 or 1981. The board is marked "PHCC-2", and has slight modifications from the original board. Eventually I expanded this board with a printer interface, a 32 KByte RAM card, a floppy controller and two 5 1/4" floppy drives. I used the P1 computer for simple word processing and for programming in assembler, Basic, Pascal and Forth. It has been sitting in my attic after I bought a IBM PC clone. Recently I decided to restore this old bit of history to its former glory, although some of the hardware and all of its software have been lost.

Current contents on this site:

asm2650

Assembler for the Signetics 2650 processor.

P1 bus signals

Description of the bus/backplane signals used on the P1. The bus is based on the Phunsy bus, so that I could easily use the floppy controller and 32K dynamic RAM card developed for the Phunsy.

PROM replacement

An modern alternative for the PROMs on the P1 board.

Popmon monitor program

Description of the monitor used by the P1.