21 Sep
2008
21 Sep
'08
5:07 a.m.
Hi,
If anyone is interested in building a FDC for their Z80 home brew computer
please contact me off list.
I am building a FDC for my Z80 home brew computer and would like to see how
it works for other builders.
The design is general enough to adapt to most Z80 systems. It has IDE and
i8272 (NEC 765) sections.
I have a working prototype on my bench and can read and write sectors and
format tracks.
It includes a simple disk monitor program for testing the FDC which could be
easily adapted to other systems.
I would like to improve and refine this design and increase test coverage
with other builders.
Thanks and have a nice day!
Andrew Lynch
21 Sep
21 Sep
2:24 p.m.
On Sun, 21 Sep 2008 09:37:51 pm Andrew Lynch wrote:
I have a working prototype on my bench and can read
and write sectors and
format tracks.
I never worked out how to format tracks on the 8272. It's one of the things
that puts me off using them. Could you describe how it's done?
The other thing that puts me off is the data clock separator. How are you
doing this?
Thanks,
Alexis.
2:43 p.m.
Alexis wrote:
The other thing that puts me off is the data clock
separator. How are you
doing this?
I can't speak for Andrew, but if you're not using an FDC with a built-in
data separator, the easiest way to do it is to use the SMC 9216, 9229,
or 9239 digital data separator chips, some or all of which were
second-sourced by Western Digital. Of course, they were obsoleted by
the newer FDCs with internal data separators.
Eric
2:45 p.m.
On 9/21/08 5:24 PM, "Alexis" <thrashbarg at kaput.homeunix.org> wrote:
On Sun, 21 Sep 2008 09:37:51 pm Andrew Lynch wrote:
Look at the code for the CompuPro Disk 1 interface. I don't have to code for
my CBIOS handy but I recall that you have to establish a 6-byte command
buffer (with the right parameters), establish the interleave (if formatting
with one) and then loop through all of the tracks sequentially, sending the
format command for each track. I used a hardware interleave so that my CBIOS
didn't have to do it.
The command buffer for my CP/M system looks like this. The fields come right
I have a working prototype on my bench and can
read and write sectors and
format tracks.
I never worked out how to format tracks on the 8272. It's one of the things
that puts me off using them. Could you describe how it's done?
The other thing that puts me off is the data clock separator. How are you
doing this? from the 8272 manual.
FMTDAT .DB F_FMT ; format command
.DB 00H ;HDS,DS1,DS0
.DB NFIELD ;N (0, 1, 2, 3) 0=128-byte sectors
.DB FSC ;Sector count (26,15,8) =1ah
.DB 01BH ;SPECIAL FORMAT GPL.
.DB 0E5H ;D (FILLER BYTE)
Rich
--
Rich Cini
Collector of Classic Computers
Build Master and lead engineer, Altair32 Emulator
http://www.altair32.com
http://www.classiccmp.org/cini
5937
days inactive
5937
days old
3 comments
4 participants
participants (4)
-
eric＠brouhaha.com -
lynchaj＠yahoo.com -
rcini＠optonline.net -
thrashbarg＠kaput.homeunix.org