On 2015-12-06 4:14 PM, Oliver Lehmann wrote:
Jon Elson <el...@pico-systems.com> wrote:
On 12/06/2015 02:57 PM, Oliver Lehmann wrote:
Hi,
I've built a Harddisk-Controller-Emulator for my system which accesses
a IDE (PATA) harddisk with an ATMega in PIO mode. It works like a charm
except for one WD harddisk. The harddisk itself works fine with MS-DOS
6.22 and FreeBSD but refuses to work with my ATMega.
On reading or writing a sector, right after the command is issued, the
error bit is set in the status register, and the error register
indicates
an ABRT.
I don't have any specific knowledge of this, but it has to be a timing
problem.
Something about the timing of the command signals is just different
enough that the drive thinks this is wrong. Sorry I can't give more
specific help.
Thought the same and added some 400ns sleeps between each of the cylinder,
sector, head commands and before I executed the read command... without
success :(
I think Jon is probably on to something.
You can check out the delays in my PIO bit-banging code here:
http://www.telegraphics.com.au/svn/picide/trunk/
I tested it on a few drives & spent a lot of quality time with the
spec...of course I can't guarantee it would work for your specific
drive, but it might give you a clue where a delay is missing.
--Toby
