Date   : Thu, 24 Feb 2005 22:22:46 +0000
From   : jgh@... (Jonathan Graham Harston)
Subject: Progress on IDE interface

I've assembled a couple of the IDE PCB to test. It's a bit fiddly
as there's one surface-mount component and my soldering iron is a
bit too big for some of the work. I haven't yet got the cards
working - I think I've bridged some tracks when soldering. There's
four people so far, including me, working on assembling a PCB and
getting it working. I believe some of them have better soldering
skills than me :)
 
Using the 8-bit prototype board, though, I've successfully
connected to two hard drives giving me four logical ADFS drives.
4GB of ADFS hard drive storage! Note that due to me
misunderstanding some of the convoluted code in ADFS the version
1.52 patch only allows access to one hard drive. The new patch
for version 1.53 on my website gives up to four drives of 512M.
 
I've also been trying to get CD-ROM access working. I've plugged
some working CD-ROM drives in with some test CDs blown with known
data. With the drives I have I haven't been able to do anything -
the drives just sit there not responding to anything except
"Reset".
 
In digging around on the Interne I discover that apparently CD-ROM
drives use a version of IDE/ATA called ATAPI, described as "SCSI
over IDE/ATA". Essentially, to control a CD-ROM drive you send a
SCSI command packet over the IDE interface. So, after ripping out
all the SCSI control code to replace it with IDE control code, it
turns out that CD-ROMs need SCSI commands.  Grrr...  Anyway, I'm
still investigating this.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
Badly formed email is deleted unseen as spam