1 Sep
2012
1 Sep
'12
11:44 a.m.
On 31 August 2012 19:55, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
Good point, yes.
Hmmm. If somebody has made more omdern cartridgs for this machien (the
ones I used were something liek 32K), thew interface to the Z88 must be
known. In which case there is some way of making a device to read them.
No I am not offering to seriously look into this, I have quite enough
machiens ot work on that I am ratheer more interested in.
They
were, yes, but then again, there are SD and CF interfaces for
earlier devices such as the ZX Spectrum now, so it is doable.
I didn;t think the system bus was availabe on either of these machines.
SO making an adapter could be 'interesting'. Didn;'t the Z88 take memeory
cartridsges, though? A cartridge to take a flash card would eb intersting...
I did some trivial research into this.
The Z88 has proprietary carts using battery-backed RAM or EEPROM.
There are carts holding a whopping 1MB of RAM now, and a gig of Flash,
I think, but there is no way to interchange them with conventional
media readers.
The NC100 has a PCMCIA slot, but it can only take 1MB of SRAM and it
is used as RAM - there is no filesystem on it, so there's no way to
read it on anything else.
Again, that surely depends on wht level of access you have to the PCMCIA
interfce on whatever other machine you plug the card into. If you can
read raw bytes from the card, then presumably there is a way to make
sense of the Amstrad's card.
I have a reason for disliking USB here, and
it's got nothign to do with
the age of the interfaces. It's that USB is too 'asymmetirc'.
Let me expalin. With RS232, and posslby simpe null modem calbes, I can
link my M100, my HP95LX, my Eposn PX4, etc, etc, etc to my PC. I can a
also link them to each other. I can, for example, link an HP95LX to my PC
nad kermit an intel-hex file to progrma in to na EPROM. I can then take
that 95LX to my workbench and plug it into my EPROM programmer nad upload
the file. Or I can transfer the file to my M100. Or I can link the M100
striagn to the PC. Or to any of my otehr machines.
YOu simply can';t do that with USB. There is no way to link 2 USB mastes
or slaves together. USB gets round the problem of null-modme cables by
making them impossible, and prventing you from doing the thigns you
needed a null modem cable for with RS232.
Fair point. There are things like USB OTG but it's rarely implemented.
OTOH, I've never once wanted to do this... I am not saying it's *impossible*. It works, very
well in some cases,
and it was a long-lived, widely-adopted standard that is of very wide
use and applicability.
All that I am saying that I find it to be fiddly and irritating -- and
failure-prone until you get the settings right on both ends. I didn't
like it when it was current and I like it less now.
Actually, had both devices in the RS2232 connection been designed to work
together (adn not be general-porpose dvices), there would be no problem.
The paramerts would be pre-set. The reason RS232 can be a bit of a
fiddle and why there are a lot of things you may have to set, is that
it's a general-purpose interface.
You thrive on such things, I am sure; my hateful administrivia is your
acvtually, no. Much of the itme I want things to work. I want to be able
to set things as I want them (e.g. I do want to be able to set 5 data
bits, 1.5 stop bits to talk to my Creed 7E), but I don't want to try
comibnations at random until it all works.
I suspect that is the reason I have no problems. Before I connect 2 RS232
devives I've not used before, I sit down for a few minutes iwth the
manual (the real manuaL) and work out just how it is going to behave. And
configure things accordingly.
fun bit of fettling, and my fun bit of
fiddling - e.g. playing with non-traditional x86-32 OSs such as Haiku,
AROS and whatnot, installing multiple Linux distros, experimenting
with FreeBSD and Solaris and so on -- might well be your wretched
waste of time and effort.
There is certainly something in that :-) However, I don;t object ot
readong an OS manual -- or even source code -- to get a classic computer
running. And I put sorting out an RS232 connection very much on that
level.
And once you have got it sorted out -- you know the settings for both
end,s oyu have a cable wired, it'll work properly for evermore. So for a
mahcine oyu are goign to use, it's worth taking a little time to sort out
how to link it to a PC and docuemtning it. Store the settings in a
configuration file on each machien, solder up an adapter or cable -- and
label it -- if need be.
For example, the HP82164 (HPIL to RS232 interface) is well known around
here for having a very unconventional use of the flow control lines. I
seem to remembr that it uses DTR/DSR as the main flow control lines. Unix
boxes tend to use RTS/CTS. I have a labelled adapter that does the
paporpriate swaps. I spent a little time etting my HPIL sytems to talk to
my linux box with this interface, suing a breakout box to get the
conenctions right. I then soldered up an adapter with the right signals
swapped round. I now just use that, I don't have to do the tests again.
It works.
-tony