RE: [N8VEM-S100:1507] IDE board BIOS question

["Bob Applegate" <b...@applegate.org>]

> What CF card you using. I and others have found that some behave strangely
> with the MYIDE software.  I have no ideas why, perhaps others have
> suggestions.   If you are not using one,  could you try working with the
> Kingston, Maxell or Patriot  4GB  CF cards. They are very common.  For
> example had reliability problems with the SCANDISK cards.

I've been using an old SanDisk 192 MB card, but I do have some Kingston
cards and will give them a try.  Forget the exact number, but it's one
that you or others listed as tested and known to work.

> Second the reset initialization pulse width to these cards is very
> critical.
> Are you using a Z80 (10Mhz) CPU, if not adjust the software delay.

It's a 4 MHz Northstar board, but I can increase the delays.

One thing that seems to help is by adding a couple extra lines in the
wrlba function to re-write the head register with the IDE-enable bit set. 
That keeps the card in LBA mode.

> The software should work for both the dual and single IDE boards.
> I'm assuming you are using the "MYIDE.COM" program BTW, without
> modifications. Right?

Correct, and I copied the critical functions from MYIDE into my BIOS, such
as the wrlba, all timing/status functions, low-level sector read/write,
etc.

I'll swap cards and see if that solves the problem.  However, it has been
a good learning experience to debug the BIOS and learn a lot more about
ATA drives.

73

Bob