Hawthorne Technologies

TinyGiant HT68k SBC


May 2, 2007

Last week I picked-up a neat single-board computer from the mid-1980's manufactured by Hawthorne Technologies. This SBC is in a 5-1/4" form factor so it could be bolted to a floppy drive. It's based on an 8MHz 68000 CPU and has a dual serial controller, 256k of RAM and a PC-compatible floppy controller. It came with a floppy-based operating system called K-OS and had an assembler, debugger and Forth language. The setup I got came complete with manuals and disks. The disks include a floppy-based operating system, Forth, a 68000 debugger and a text editor.

The picture shows the memory at the top-left. The WD1770 floppy controller in the upper-right. The 68000 in the lower-left corner (with the ROMs immediately above it). The 68681 dual serial controller is in the lower-right corner. The remaining chip next to the ROMs is the DRAM refresh controller.

The floppy connector is a standard PC-style 0.1" dual-row header (to which I have connected a header-to-card edge adapter). The floppy cable is from a Tandy CoCo disk drive. The power connector for the board is a standard PC floppy connector, so you can use almost any surplus power supply (I'm using one that's 5v/4a and 12v/2a that I got from BG Micro or Marlin P. Jones...I forget which).

The basic specs are: 68000 @ 8MHz, two serial ports, one Centronics parallel port, 128k of RAM (expandable to 512k), an expansion bus and a PC-compatible floppy controller enabling the use of 3.5", 5.25" or 8" drives (OS comes configured for 5.25")...all in a 5.75" x 8" size. The list price was $395 and it came with a ROM monitor, disk-based operating system, assembler and editor. A Forth interpreter was available for an additional $50.


    The following are images of the disks. I used Teledisk version 2.16 to make copies of the disks. Teledisk is available here: http://www.classiccmp.org/dunfield/img/teledisk.htm


    Below are scans of the manuals that came with the board:

    I've found a typographical error in one of the manuals. On page 4-5 of the system description manual, there is a pinout of P3 which is the floppy disk drive connector. The disk select pin assignments are wrong:

Pin    Old Function    Correct Function

6        DS0            DS4

10       DS3            DS1

14       DS1            DS3


    There was a newsletter from Hawthorne for this SBC, but I only have a few issues. Here they are:

    This is another 68k newsletter, but I don't know much about it (PSM):

    Here is another 68k-specific newsletter (PSM):

Random Documents

The Computer Journal (TCJ) Articles

    The HT-68K was featured in several articles in TCJ. I don't have the complete series of TCJ, so I might have missed some issues. Here are the ones I could find:

Contributed Programs


    The system ROMs were 27128 250nS devices (16k x 8) in a split (high-low) arrangement. The text represents what was written on the EPROM labels.



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Last updated 2023-02-12 12:51 -0500