22 Nov
2000
22 Nov
'00
4:28 a.m.
--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > >
Apologies - a habit left over from another mailing
list, where it is customary.
Mmmmm! Lovely stuff! I wonder if me old mucker from
secondary school/uni still has that box of really old
smelly eproms - i'll give him a call and find out...
Damn damn and triple damn! I just got the latest
MAPLIN cataloge last night - they don't do the 8255
card anymore, they do a carp replacement - using TTL -
costing, wait for it, 100gbp! They can *get lost*
i'll build my own darned pc card - I wonder if farnell
still do 'blank' ISA prototyping cards?
I need to get on and build up my PCB making equipment
again - so I can build myself, and other serious
computer geeks, special cards :)
How about a dual 8255 based card? 48 bit programmable
digital IO anybody?
Single density floppy controller?
Oh! The list could be endless!
MB8877a which I believe is a
5voltonly WD1793
i.e. A double density controller. There are obviously
--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote:
Incidentally, you don't need to send me a private
copy of e-mail that you
post to the list. I read classiccmp :-) OH! Something
else that became obsolete before I
started taking things apart...(I'm only 23)
Wait until you come across 1702 EPROMs. They run
from a 14V supply,
conventionally called +5V and -9V (there is _no_
ground pin on the chip).
Inputs and outputs are TTL-compatible wrt a 'ground'
5V below the +ve
rail (so if you use +5V and -9V, the address and
data lines link up to
normal TTL).
Programming 1702s is even more 'fun' and involves
taking several pins up
to quite high voltages... That would
explain rather a lot. I'll have to
build
me an eprom dumper then.
I'll get one of them 24 bit (8255 based) ISA IO
cards
from maplin (about 25 quid ISTR) and make one up.
Seems reasonable.
Since the COS ROMs are readable by the 380Z's
processor (unlike the
address decoder, say), you could presumably read the
ROMs by a little
program on the 380Z and squirt the data out of the
serial port.
I could if I had any data on it :(
> Are you
sure this is a standard RML disk
controller? Yes... This sounds like a double-density card
alright. And it's a card
I've never seen and have no schematics or data on
:-(.
Which means it may well need a non-standard system
disk as well,
something that none of us seem to have :-( :-(...
Damn! Foiled! Looks like i'm going to have to go
with Dwight's (sp?) suggestion and write my own bios.
That should get me back up to speed with the old Z80
again...i'll try any system disk anybody sends me
anyway - I can alway find the correct controller card
for them. I think it was Monsier Honniball who had
some RML380Z bits...
Dave.
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