Sardis Technologies DMC Floppy Disk Controller for the CoCo

(Yes, I now know the red bar should slope in the other direction, but I had already printed a thousand stickers like this before I was told.)

(This page is still under construction.)

The "No Halt" Dual Mode Controller (DMC) from Sardis Technologies is an enhanced floppy disk controller cartridge for the Radio Shack Color Computer (CoCo).

DMC features:

• works with CoCo 1, CoCo 2, and CoCo 3, at 0.895 MHz and 1.79 MHz
• supports new "no halt" mode for improved user experience
• also supports original "halt" mode for compatibility with existing software
• no adjustments: all-digital data separator and write precompensation
• supports single and double density
• uses Western Digital WD1773 controller chip (p.1-1 in data book, 22.3MB .pdf)
• 8KB or 32KB buffer/cache memory
• 28-pin ROM socket for 24-pin or 28-pin ROMs, dual-DOS capable
• includes Radio Shack DOS 1.1 ROM
• gold-plated card-edge connectors for reliability
• 4-layer board with soldermask and silkscreen
• includes SDisk or SDisk3 driver and SFormat program (licensed from D.P. Johnson)
• requires Multi-Pak Interface (explained in brochure)
• 2-piece metal case

The DMC controller started shipping in July 1987, and was sold world-wide for several years. And, yes, a few people are still using the DMC, over 30 years later!

Enhanced "no halt" drivers are provided for Microware's OS-9/6809 (and NitrOS-9/6809), both Level I and Level II, for the CoCo 1/2 and CoCo 3. (Requires PAL-4 board installed to use latest version.) The drivers are based on licensed copies of D.P. Johnson's SDisk and SDisk3.

Rainbow magazine first mentioned the DMC controller in an article by Dale L. Puckett, and in the report on the April 1987 RAINBOWfest. The book Tandy's Little Wonder, the Color Computer mentions the DMC controller on page 65, but incorrectly states that Sardis Technologies had dropped out of the CoCo market by 1988.
///////// etc. ////////////

I sold my last remaining inventory of boards, components, and metal cases to a customer in Canada in 2013. If you are interested in purchasing any metal cases or other items, contact me, and I will forward your request to this person.

Detailed background information is provided in The DMC Story.

(Click on a picture for a larger version.)

Advertisements in '68' Micro Journal (1.4MB .png) and Rainbow Magazine (1.7MB .png).
Pictures of assembled DMC board (minus PAL-4 board) (540KB .jpg) and bare DMC board (179-203KB .jpg).
Pictures of PAL-4 board (132-156KB .jpg).
Picture of DMC metal case (130KB .jpg), and assembled board used for testing over 200 PAL-4 boards (note IC sockets and yellow and blue wires for PAL-4) (556KB .jpg).

	Brochure for DMC Floppy Disk Controller. (2.9MB .pdf scanned image)
	Hardware Manual for DMC Floppy Disk Controller. (preliminary version dated 1987-Jul-14) (771KB .pdf scanned image)
	Schematics for DMC controller and PAL-4 board. (last revised 1988-Oct-04) (171KB .pdf scanned image)
	User's Manual for SDisk3-DMC Software for OS-9 Level I. (preliminary version) (not available yet) (??MB .pdf scanned image)
	DSK image (35T/SS/DD CoCo OS-9 format) of SDisk-DMC Software for OS-9 Level I, as distributed. (requires the PAL-4 board installed) (24KB .zip)
	User's Manual for SDisk3-DMC Software for OS-9 Level II. (preliminary version #3 dated 1988-May-15) (2.1MB .pdf scanned image)
	DSK image (35T/SS/DD CoCo OS-9 format) of SDisk3-DMC Software for OS-9 Level II, as distributed. (requires the PAL-4 board installed) (41KB .zip)
	DMC metal case drawings. (699KB .pdf) (Note that a thin fiber washer needs to be placed between the PCB and each standoff to get the right spacing.)
	Sample pages from "final" version of "OS-9 Level II SDISK3-DMC Software User's Manual". (was never completed or released) (1.2MB .pdf scanned image)

"FLEX" was a trademark of Technical System Consultants (TSC).
"OS-9" is a registered trademark of Microware LP.
"Radio Shack" and "Color Computer" are trademarks of Tandy Corp.
"MS-DOS" is a trademark of Microsoft Corp.

Last revised 2024-Apr-04 13:26 PDT.
Copyright 2018- David C. Wiens.