New subject: ISA prototyping boards at RSLC, was Re: intro and RML380Z

21 Nov 2000

--- Tony Duell &lt;ard(a)p850ug1.demon.co.uk&gt; wrote: > > 
...

 --- Tony Duell &lt;ard(a)p850ug1.demon.co.uk&gt; wrote:   
 Incidentally, you don't need to send me a private
 copy of e-mail that you 
 post to the list. I read classiccmp :-) 
Apologies - a habit left over from another mailing
list, where it is customary.

...
   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... 
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...

...
   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.

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!

...
  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?  MB8877a which I believe is a
5voltonly WD1793

 i.e. A double density controller.  There are  obviously

...
  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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