The P112 subject pops up fairly often on the Usenet newsgroup comp.os.cpm. Reading it will help you get the most out of your P112.
Assorted pictures of my P112.
The P112 is a stand-alone 8-bit CPU board. Typically running CP/M (tm) or a similar operating system, it provides a Z80182 (Z-80 upgrade) CPU with up to 1MB of memory, serial, parallel and diskette IO, and realtime clock, in a 3.5-inch drive form factor. Powered solely from 5V, it draws 150mA (nominal: not including disk drives) with a 16MHz CPU clock. Clock speeds up to 24.576MHz are possible.
The P112 board was last available new in 1996 by Dave Brooks. His page is here. In late 2004 on the Usenet Newsgroup comp.os.cpm, talk about making another run of P112 boards was discussed. I decided to step forward. With Dave Brooks blessing and the assistance of others, new boards were fabricated.
I don't have any more kits left. I started taking preorders in August 2010 with the intent of getting 35 kits presold. That would have allowed me to go forward with having 100 boards made. The cutoff date in October was chosen because that was 60 days later and therefore I could issue refunds through Paypal without losing the Paypal fees. I wasn't able to make that minimum and so all preorders were refunded.
I hope to be able to do a new run a few months after I get a new job. That run will be entirely self-financed with no preorders necessary.
This P112 board project is very different from the one Dave Brooks offered. The board itself is the same, but that's about all that stayed the same. The "native" operating system is now ZSDOS, an enhanced replacement for CP/M 2.2. The old DOS+ boot disk can still be used, but is discouraged. UZI-180, a Unix clone for the Z180 processor is available in a version specifically customized for the P112.
Instead of getting just a board with surface-mount parts mounted and little else, buyers get a complete kit. Except for a chassis, power supply, floppy drives, and tools (like soldering stuff); you get everything you need to get started. The documentation has been pulled together into a single PDF file, updated, edited, and cleaned up. A copy of the Walnut Creek CP/M CD dated Nov 1994 is included. No permission was needed to replicate it. Another CD is provided which contains the documentation PDF and lots of other stuff that was deemed interesting (like UZI-180).
Another nifty thing about the P112 is that you can get an IDE interface for it. Terry Gulczynski has adapted Tilmann Reh's GIDE design to an expansion board for the P112. With this, you can connect a hard drive, CD drive, or flash drive to a P112.
Something to keep in mind about the GIDE design is that it depends on the connected drive to be able to make 8-bit data transfers. Most newer parallel IDE drives only operate in 16-bit mode. Here is an example of how this problem was solved with a different Z80-based IDE interface.
No problem! One of my cohorts, Terry Gulczynski, will build and test your P112 for you. He has other services like adding more memory and adding an IDE interface. If that's what you want, please tell me when you email me. He doesn't have any P112 kits. The idea is that you pay me for a kit and I'll send it to Terry for assembly. He'll then send it to you.
Check out his website at http://home.roadrunner.com/~tgcons/ for more information.
The following disk images are retained for hysterical raisins.
If you have any questions or comments, feel free to email me at dave@661.org.
This page was last updated on October 15, 2010