dlightman
Experienced Member
Even though it wasn't supported by Tandy the original 68000 "long" or "dog-eared" CPU board could be upgraded to support the DMA BURST Mode feature needed to run XENIX 3.x. You can actually find a lot of info out there that it was done but for whatever reason nobody ever documented the specifics.
Since the original CPU board is the most prolific of all the 68000 boards and XENIX 3.x is such a huge improvement over TRS-XENIX I very much wanted to see this modification resurrected. Lucky for us a long board with the burst mode modification made its way to me. I dumped the PALs, documented the modifications and successfully applied them to one of my own stock long boards.
The modification is very simple to do and easy to reverse without permanent modifications to your board.
Here is archive with everything needed to perform the modification: https://bit.ly/34DaHQu
Picture of the board I modified:
Since the original CPU board is the most prolific of all the 68000 boards and XENIX 3.x is such a huge improvement over TRS-XENIX I very much wanted to see this modification resurrected. Lucky for us a long board with the burst mode modification made its way to me. I dumped the PALs, documented the modifications and successfully applied them to one of my own stock long boards.
The modification is very simple to do and easy to reverse without permanent modifications to your board.
Here is archive with everything needed to perform the modification: https://bit.ly/34DaHQu
Picture of the board I modified:
