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California Computer Systems - 2422 FDC  Board
This was a fairly standard FDC board.  The only thing unusual was that by modifying the board you could get it to work with PerSci drives. It utilized the Western Digital 1793 (non inverted data bus 1791) FDC chip.

CCS-FDC Board-2

CCS's 2422 Floppy Disk Controller supported single- and double-density data formats, single- and double-sided 5.25" and 8" drives, and provided a 2K ROM containing software debugging routines and a bootstrap loader for loading CP/M (Digital Research's single-user operating system) from diskette. The 2422 was designed especially for use in CCS's system 2210, but provided a number of user options for compatibility  with  other   systems  and   software.
The   2422   incorporated the  following   features: The well written manual can be obtained here.
The schematic can be seen here.

"This board is modeled after the CCS Rev B controller. Incorporated are a couple of the known fixes to correct some timing problems. The "Memory Map" prom option was not included in this rev, which I have never seen used, and was also not supported in the CCS BIOS. There is an option for using GALs instead of the bi-polar proms (74s287's), which are hard to find, and need specialized programmers. Two 22V10 GAL's replace the CCS U22, and U23 proms. I structured the GAL pins in way that you can use either the GALs, or the proms, on the same board with just 1 jumper. I also added the option for the Pololu 5V regulator. There is a cut trace option on the solder side if one wanted to use a more common 2732, vs a 2716 / 28C16. There is also a set of jumpers for the 8" "TWO SIDED" signal to be emulated for either Drive A, Drive B, or ALL drives, if you use drives that do not provide the "TWO SIDED" signal (The CCS controller, and the Compupro Disk1A, needs this signal). This is especially useful when using Drive Emulators, or using 3.5" drives as 8" drives, etc.. I added a mini led to indicate that "TWO SIDED" is enabled.  Functionality of this board, as well as the chip layout, matches that of the CCS 2422 Rev B controller."

Greg Beat has submitted the following support information for a reproduction of this board done by Richard Camarda and Todd Goodman. See here



The code for the GALs is here:-
KiCAD Files.ZIP for the above Rev E board. (Supplied by Rich Camarda/Todd Goodman). Use KiCAD 4.0.7 or later.

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This page was last modified on 02/28/2021