Apple II IDE interface

["St�phane Guillard" <stephane.guillard@steria.com>]

Hi all,

I've designed a very simple but fully functional IDE interfacefr Apple II's.
At the moment I run it in a IIe, but also tested it in a IIgs. The interface
is based on standard 74LS chips, using 3 LS32, 1 LS04, 1 LS28 and 2 LS373,
so there is no need for programming PALs. It can be built up for $5 or so.
Schematics will be made available as soon as I have a bit of time to clean
them up.

The interface maps the full IDE registers as well as a MSB latch (IDE data
transfer is 16 bit) in the 16 byte window of the slot in which it sits, so
it is able to handle full 16 bit transfers (by latching MSB at LSB read time
and reading it after LSB). Thus all IDE functions work (drive info query,
512 byte sector transfers etc.).

The driver I am working at is written in ProCode assembly so that it goes
fast. It handles fdisk Master Boot Record (MBR) and LBA FAT32 partitions, so
that when you put the HD in a PC you can use the partition normally and when
the Hd goes back into the apple you see the same files. The software is not
finished at the moment, but I work on it almost each night. I'm able to read
the FAT32 dir and files at the moment, work is still left for writing new
files.

I try to keep the software as small as possible and relocatable, so that it
can be loaded both with old DOS3.3 or ProDos, and let you transfer files
from floppies to HD and back. I guess there also could be some interest in
making a complementary patch which would make the file access go to HD from
normal DOS or ProDos calls, so that software using DOS API can work with the
HD. I will look at it later. I don't intend to make a ProDos block driver,
as this would limit the use of the HD to 2x30 MByte partitions, and would
not be compatible with other platforms.

Thought this might be of interest to some of you,

Regards,

PS : a ugly thing : I have both an original and a cracked licence of
ProCode, and the original says "you're using a copy" wile the cracked works
fine :-)

Regards,
--
St�phane Guillard - stephane.guillard@steria.com
T : 04 72 52 35 40 - F : 04 72 52 35 55 - M : 06 09 41 78 40