SCSI 1 (and possibly SCSI 2) do not use DMA, it predates DMA bus mastering topology.
Therefore, the ACARD is not going to have DMA capability or any way to enable or disable it.
If you have concern whether the SCSI is working at all, you could get a SCSI Internal Zip.
Set to ID 0- as a test it shouldn't be too expensive and we would expect that at the end of this test, the Zip is formatted successfully from a non-PLUS OS.
Usually in my troubleshooting techniques I assume something doesn't work / not working properly as opposed to assuming it does / should work until I have proven otherwise.
I had 6 bridges (4 x 7722) which I sold for use with ATAPI zip drives) and (2x 7220UW).
I updated the firmware to latest for the correct PCB version (what I have now) and tested it in my Emax 1 and 2... and one of them has been working in my Emax 2 ever since.
This is a test I have done and verified with my bridges.
I would do a test with this config for the bridge.- Get an 500MB or smaller IDE drive (smallest you can find from a reuse shop or something) or IDE Zip drive and test bridge with that.
The bridge could have an issue, but the CF adapter could work fine.
Ted, I will assume for the time being that the 6.89 firmware on your board REV ??? should be reasonably comparable to my REV 3.1 board running 3.89 and that my Emax should likely be able to communicate with 3.89 unless someone can confirm otherwise.
I Tested the Addonics ADIDECF Adapter WITHOUT the DMA jumper set, but Emax 1 still gives the HD Error.The generic looking Hexin HXSP-2108P CF Adapter I got has no DMA jumper, though specs say it does support DMA but I don't know if it's possible to disable. Users in the eiii forums reported this card as working for them but so far it doesn't work for me.
Q: Is there a way to disable DMA from the Acard 7720U?
The Acard activity LED does NOT light up when connected to Emax and I attempt to format the CF. I would expect this to behave like it does in Windows - i.e.the activity LEDs light on both the bridge & the CF reader when reading/writing.
Q: Since neither the bridge nor CF adapter LED lights up and the bridge is first in the chain, do you suspect the Emax is not sending commands to the Acard? Or is the Acard not able interpret the Emax SCSI commands?
Thanks,Jim