Ruud
Veteran Member
AFAIK XT-IDE does not use DMA on a 8088 machine to exchange data with an HDD or CF card. If XT-IDE does, then I have a problem. If it doesn't, then I still have a question.
But first: I created this little machine: http://www.baltissen.org/newhtm/mini-v20.htm , a PCB containing an 8088 or (preferably) a V20, RAM, ROM, one ISA slot, a 16450 UART and some glue logic. Not having DMA means I need to exchange data with a FDD by polling the registers. But regarding an HDD, if XT-IDE does not use DMA at all, I don't see almost any reason why I cannot use it as-is. Let's assume that:
- the INT 10h routines for the video are replaced by ones sending the data to the UART,
- the keyboard routines are replaced by routines reading data from the UART
- the INT13h are replaced by ones not using DMA
My question: am I overlooking something?
But first: I created this little machine: http://www.baltissen.org/newhtm/mini-v20.htm , a PCB containing an 8088 or (preferably) a V20, RAM, ROM, one ISA slot, a 16450 UART and some glue logic. Not having DMA means I need to exchange data with a FDD by polling the registers. But regarding an HDD, if XT-IDE does not use DMA at all, I don't see almost any reason why I cannot use it as-is. Let's assume that:
- the INT 10h routines for the video are replaced by ones sending the data to the UART,
- the keyboard routines are replaced by routines reading data from the UART
- the INT13h are replaced by ones not using DMA
My question: am I overlooking something?