XT-IDE adapter with CPLD v2 working

Pietja successfully built and tested our CPLD-based XT-IDE adapter v2. These boards give old XT PCs the ability to interface with IDE hard-drives and compact flash cards. There are still lots of these old boxes out there running medical and industrial equipment, and the XT-IDE cards keep them going with modern drives.

The Vintage Computer Forum’s original XT-IDE design uses discrete logic chips and all through-hole parts. Our version puts all the chips into an XC9572XL CoolRunner-II programmable logic CPLD.  We design the controller logic in software, compile it, and upload into the CPLD.

Occasionally someone finds a small hardware hack that increases XT-IDE performance.  “Chuck MOD” rewires a few traces to get a considerable speed boost for example. On the original hardware this was done by cutting and rerouting a trace with a jumper wire. We just upload a new design with the changes into the CPLD.

Our v1, 1va, 1vb XT-IDE hardware only combined a few of the logic chips into the CPLD. After testing the concept though, we moved to a 100% CPLD-based design in v2. It’s a blank canvas with an EEPROM chip that can be a disk controller, or something completely different.

The very first revision of the v2 hardware works perfectly so far.

Here’s a performance benchmark using the stock BIOS and logic:

  • Write Speed : 214,06 KB/s
  • Read Speed : 243,11 KB/s
  • 8K random, 70% read : 21,15 IOPS
  • Sector random read : 65,05 IOPS
  • Average seek, including latency, is 15,67 ms.

The XT-IDE adapter with CPLD v2a source package includes the latest hardware files and Pietja’s bitstreams for v2 and v1 adapters. We have a couple of free PCBs available to vintage hardware maintainers. Join the hacking in the forum.

A big thanks to Pietja, J1mbo, and alanh for help developing and testing the hardware. A huge thanks to members of the Vintage Computer Forums for their original design and the XTIDE universal BIOS drivers that make our hardware possible.

Join the Conversation


  1. How do I get my hands on one of these? Do you have any PCB boards left? Can I get someone to build one for me???? ;)

    1. There are still some PCBs, and I can send you one, but I don’t know anyone who will build it for you.

  2. Can you tell me if this is available for sale. I am interested in one as I do collect retro computers currently trying to refurbish my KAypro III and Compaq Portable III

  3. I’d like to buy one of these boards. Isn’t anyone offering built units? I don’t have the steady hands or eyesight to build one myself.

  4. I am very interested in one of them. Other than building the board, is there anything else I need to do? Other than tweak the bios? or are there instructions somewhere? Thanks.

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