Hi all. I'm working on a custom ISA board, and want to use the MS-DOS "debug" command as one option to buzz it out. The debugger has an 'I', or input, mode where you tell it an address in I/O space and it reads a byte back to you.
And that works. Sort of. The custom board is all based around 16-bit I/O access. If i go to the address of interest + 1, i get the high byte of the data. But if i just go to the address of interest, all i get is FF.
Im guessing this is because this board has no latch, it just extends the bus into the instrumentation i'm working on. I have to do a 16-bit access to see the low byte of the word. The board works fine with the driver software that was written for it, so i know everything else works.
Shouldn't there be a way to put debug into 16-bit mode? I'm pretty sure the IN and OUT instructions have a 16-bit addressing mode. But everything ive seen about its I and O commands are for single bytes.
Now i know there's a less simple way to do it: use Debug to assemble a tiny program. But im trying to avoid this solution, or installing any third-party software. Part of the idea is the ability to tell a customer over the phone to just pull up a command prompt and read bytes back to me if they ever have a problem.