IDE knowledge anyone?

Oliver Lehmann lehmann at
Tue Dec 8 01:16:30 CST 2015

Hi Warner, hi Brad,

I have an old russian 50MHz dual-beam osciloscope but without
any storage functionality. ->
I guess it would not be that easy to actually display the whole
communication cylce. I could see how good the flanks are, but I guess
my AVR does it quite well.

In the meantime I checked the FreeBSD ata driver as well as Linux
ata driver and I also took a look on FreeDOS. I don't see that much
differences to how I issue the Read/write commands.

This is my circuit:
It changed a bit in the meantime regarding the reset logic and I moved
2L1 from the PATA-Connector to the free AVR-Port, but nothing significantly

This is my ATA driver and in the directory is all the other Code for my

I'll probably dig out my old 486 mainboard with an old ISA IDE Controller
to check if this old thing is able to work with that harddisk. All newer
stuff will do WDMA or UDMA and not PIO like I do with my AVR.

If the 486 is also able to work with that disk, I see two options...

a) get a cheap "open logic sniffer" (logic analysator) and see how good
the timing is (but as I said I added massive delays without success)

b) just accept that there is hardware around in the PC sector which works
"sometimes" ;)

I don't intend to use this harddrive anyway, I just fear that I made a
misstake in my circuit or the code and others intending to use my
emulator also experiencing problems with their drives too.


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