Roll of Honor - Point of view: ZX Spectrum system bus.

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(C) Ovsyannikov Andrey
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 Dear VTS'99.

   First of all, I would like to thank
to give you for what you did not consider to be work
           state your vision of the situation
           on this issue.  However,
           hello... Very interesting
           was reading your RE: on my
           article. In general, your opinion is mine
           close and understandable, although a number of
           marriage seems controversial to me and yes-
very much so.
   Let's start with the tire. I agree with you that shi-
It’s already on many machines. And almost in
it is unified for everyone. But what to do with
this "almost"?  I mean that the original
nal connector "Sinclair ZX-Spectrum" co-
kept, among other things, and colorful
digital signals, as well as a brightness signal. And
what do we see here in "Scorpio" and
"KAY"? What about "Profi"? Next, at "Profi" on
system connector outputs the signals of the left and
rightchannels, turbines, and therefore located
The position of the “compatible field” pins has
appears "slightly shifted". And, as a consequence,
data view, - “almost”, for connection
"alien" periphery has to re-
movers and various kinds of “coordinating devices”
swarms." But the tire is designed as
times so that problems of this kind do not
stood. Where to put additional addresses?
on machines with memory more than 48KB, additional
body signals, say, for "DMA Sound
Card"? This is where it comes in (pops up)
problem with soldering iron and scalpel...
   One of the solutions is suggested by RS.
   Remember the difference between ISA-16 from ISA-
-8? Yes, of course, with the presence of additional
slot. At the same time, both have the main slot
one to one, and any card ISA-8 will work
to work here or there. Hence the question:
a completely “non-obvious” conclusion emerges: - everything
additional signals, as expedient
we and are equivalent to the basic ones they do not seem to be
If you do, you need to output it to an additional
slot Moreover, recently
there was a tendency towards an increase in targeted
space, introductionmulti-level system
topics of interruptions, etc. And so that some
"crazy guy" didn't put anything in there
“not at all native”, you can simply increase
determine the distance to the additional layer
ta. A certain number of contacts can be
leave blank for possible modifications and
modifications.
   Now I will risk touching on the topic of “everyone
square centimeter of printed circuit board."
As the late John Lennon said: -
"Imagin'...". Imagine a matherboard
with five to six slots similar to above-
described. To complete the picture, let's add more
a couple of technological (other constructive)
design), two to four slots for
SIMMs, IDE - interface, keyboard interfaces
atures, joysticks, Kempston mice, magnetic
background. That's all. Well, you can add a little
crumbling.
   Taking a closer look at the diagram
you can always select processor modules,
the RAM node itself, the TV output circuit and
etc. If these nodes are executed in the form of
individual cards with varying degrees of in-
integration (say, into a processor card up to
add ROM, memory management ports, AY),
then there will be much less problems with the upgrade
- the cards change, the “mother” remains, and for-
change, say, Z80 to Z180 ( 280, 380, 604,
21364 ;-)) comes down to replacing the card, but not
if not the whole complex (shove your
brake in... (no offense, these messages
constantly crawling out here and there (:-) ))).
Moreover, at first, as a process
of the weed module, your stan-
Renky (and not really) _who-are-you-using-now-
et_.
 Why "ZX-BUS"? Not everyone has
powerful processors cost lei, not all users
involve KAY and buffering (literate) in ob-
In general case it is necessary.
   Now a few words about the notorious
sixteen-bit.

   Usually:

 ┌─────┐ ▐
MD0 ─▐──┤ AND ├────D0──▐
MD1 ─▐──┤ Р ├────D1──▐
MD2 ─▐──┤ 2 ├────D2──▐
MD3 ─▐──┤ 3 ├────D3──▐
MD4 ─▐──┤ ├────D4──▐
MD5 ─▐──┤ ├────D5──▐
MD6 ─▐──┤├────D6──▐
MD7 ─▐──┤ ├────D7──▐
 ▐ │ │ ▐
 ▐ ─┤C │
 ▐ ─┤OE │
MD0'─▐ └─────┘
MD1'─▐ Signals from both converge here
MD2'─▐ RAM lines and from the same bus
MD3'─▐ data goes to TV circuits.
MD4'─▐ In this case, RAM lines can
MD5'─▐ work only one by one.
MD6'─▐
MD7'─▐


   And this is what I suggest:


 ┌─────┐ ▐
MD0 ─▐──┤ AND ├────D0──▐
MD1 ─▐──┤ Р ├────D1──▐
MD2 ─▐──┤ 2 ├────D2──▐
MD3 ─▐──┤ 3 ├────D3──▐
MD4 ─▐──┤     ├────D4──▐
MD5 ─▐──┤     ├────D5──▐
MD6 ─▐──┤     ├────D6──▐
MD7 ─▐──┤     ├────D7──▐
     ▐  │     │        ▐
     ▐ ─┤C    │        ▐
     ▐ ─┤OE   │        ▐
     ▐  └─────┘        ▐
     ▐                 ▐
     ▐  ┌─────┐        ▐
MD0'─▐──┤  И  ├────D0──▐
MD1'─▐──┤  Р  ├────D1──▐
MD2'─▐──┤  2  ├────D2──▐
MD3'─▐──┤  3  ├────D3──▐
MD4'─▐──┤     ├────D4──▐
MD5'─▐──┤     ├────D5──▐
MD6'─▐──┤     ├────D6──▐
MD7'─▐──┤├────D7──▐
 ▐ │ │ ▐
 ▐ ─┤C │ ▐
 ▐ ─┤OE │ ▐
 ▐ └─────┘ ▐
 ▐─MD0 ▐
 ▐ .
 ▐ .     These signals also come
 ▐─MD7 to TV circuits, but now
 ▐─MD0' they can go AT THE SAME TIME
 ▐ .     with appropriate
 ▐ .     changes in shapers
 ▐─MD7' CAS and WE signals.
 Signal C for both registers
 the ditch can be common, and
 OE must be separate,
 forCPU can't read
 "full front".

   You asked where to put the extra
What are the data bus bits? With this situation
I don’t see them, neither does the processor (doesn’t see them).
You are talking about "perversions" in coding. What
but when the tricolor appeared, it seemed
science fiction, now I (and I’m not the only one)
co) I can’t watch it for more than 15 minutes -
My eyes get very tired. The point is that
for 20 mS you can draw only one image
wound (during this time it will only be displayed),
for 40 - 2 (this is the limit that the eye
begins to notice a change in personnel, notice something
notices, but the brain does not realize it), for
60 - 3 and this is not skipped by any coding -
No, that’s how traditional ULA works. Mine
The same solution allows you to issue display circuits
two bytes at once (four - if you reverse
attention to attributes), i.e. make two(4)
color planes for the same 20 mS. (This
one of the possible applications of this multi-
ki).
   About microprogram automata. Yes, usually
but they use RE'shki and RT'shki,
sometimes RF'ki, although who bothers to use it,
say, 555RU2, for example?Download tu-
So what do you need, change it when you need it? On the other hand
side, if you have covered somewhereKP11,
You just drop it off and throw it away, so
why not do the same with the scorched RT'
shkoy? You just need to give it along with the diagram
firmware, unless, of course, this is an arch-
secret.
 "You can't cut the computer!" With both hands,
but, my dear opponent, try to guess,
where did I get a megabyte then?
Pentagon with port #7FFD for reading, under TR-
-DOS 6.05E, and how it will be pro-
all turbocharged, how do I get there?
to a blank ROM page (NeOS will be there),
I'll hang up the cache, use the curb and reverse
move for Digital Sound and video with four
(for now) colors per pixel, 64 screens, and that’s it
is this without a soldering iron and scalpel? What about
Locky if I say, then I think you too
I wouldn't mind. It’s just that they, the bourgeoisie,
Anything is possible, with us - the bourgeoisie can only do so
Moscow and St. Petersburg, and the rest of us - not
bourgeois, and that means we won’t see video footage
tsessor, like your ears, so you have toto be exorcised.
   In conclusion, please forgive me if
who I offended or hurt was not in my thoughts,
also for the lack of footnotes and copyrights -
such a mountain of materials was shoveled that this
the list would take another couple or three volumes
equivalent to this opus. Forgive me for this -
I am, but I think not for long. Write to
"DEVA VU" or personally to me at:

     347340 ROSTOV REGION.
 VOLGODONSK,
 st. LENINGRADSKAYA 15 sq. 39
 OVSYANNIKOV ANDREY PETROVICH
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