This card will provide 32k or 64k of ROM via a flash chip installed on the board. This chip can be programmed via software within DOS. It will allow you to add your own custom BIOS extension code for any purpose you may have. You can select a base address between 0x8000 and 0xF800 and provide either 32k or 64k of memory space. This board also supports IBM XT slot 8 compatibility.
This card should work in any PC with an ISA slot that supports BIOS extensions. Even without BIOS extensions, you will be able to access the memory on the card within DOS, it just will not present a boot-time message. To program, we use the Lo-tech XTIDECFG.COM, which is found under the Lo-tech Compact Flash adapter Wiki. To erase the chip, we use the Lo-tech XT-CF utility flash.exe. This is available under the Wiki as well. We ran into issues on at least one system where we could not use the flash utility to program the chip, it will only erase for some reason. After it erases the chip, you can then use XT-CF Utility to write your contents. Results may vary, so please try this approach if you run into a problem with the utility.
Purchase is for PCB only. Parts will need to be purchased separately, and assembled.The link below contains a full bill of materials to complete the build, as well as the instructions on how to set the board jumpers.
***The Lo-tech wiki is a little out of date. The board was updated to add slot-8 support for the IBM XT. There is one new IC on the board, one additional capacitor, and a change to the resistor pack. In addition to the parts listed on the wiki below, you will need:
1 – 74LS33 – IC3 – Mouser Part Number: 595-SN74LS33N.
1 – 8-Pin SIP 10k 7-Resistor Bussed – Mouser Part Number: 265-10K-RC. (Replace RN1 from the Bill of Materials in the link below.)
You will also need one more 0.1uf or 100nf capacitor. You may also want a 14 pin DIP IC socket if you are socketing all of your ICs.
Lo-Tech ISA ROM reference page: wiki page.