┌─────────────────────────────── ───────────────────────────────╥
│ Revision ║
╘═══════════════════════════════ ═══════════════════════════════╝
We offer you a modification that will add to your
Speccy new graphics mode. This mode allows
color every eight dots horizontally with your own two
flowers, instead of the standard 8x8 dots. To development
I was inspired by the graphic editor "MEGA SCREEN", in which
a similar effect is achieved programmatically. But big
consumption of processor time, image size is only
quarter screen (128x9 pixels) and attachment to the INT signal,
which is very different on different Speccy models, lead to
the meaninglessness of the practical application of pictures obtained in
this editor. You can read about using the mode in
"X-RAY#2", and here I will tell you how to get it.
For modification, you only need a button with two or three
switching groups (depending onspecific model
computer). Below are several modification schemes.
computers, the circuit diagrams of which I have, but in principle
it is possible to modify any Speccy. On all diagrams the button
be in the normal Speccy mode position, the inscription
“tear off first” means that the output of the microcircuit needs to be
bite off near the board, and then bend and solder the wire to it
from the button. I advise you to bite off and bend the lead, and not
cut the tracks on the board suitable for it, as they can
go to the conclusions of other microcircuits.
For those who understand hardware, I advise for more
reliable operation instead of a button with several groups
use a multiplexer (for example KP11), and it’s already
switch with a button with one group of contacts. For those who
wants to modify a computer that is not here, I’ll try
explain what this hardware trick is based on. First find
multiplexer (usually KP11) and logic element, which in
in normal mode they serve to form part of the video RAM address, and
switch depending on what is read
video controller at the moment, byte points or bytes
attributes, they need to be locked in positionwhen they
form the address of the dot byte. Then you need to find one of
multiplexers (usually KP11 or KP12), from those that are used
to control RAM, one of the inputs of which is connected to the case.
This input is responsible for bit A13 of the video RAM, which in normal mode
always be in "0", since video RAM addresses do not exceed
23295. A signal must be supplied to this input, which is at “0”
when the dot byte is read, and to "1" when the byte is read
attributes (this signal, or its inverted copy
used to switch the multiplexer which we
blocked). Thus, the video RAM address when reading
bytes of points will be the same as in normal computer mode, and
when reading the attribute byte, differ from the point byte address
only bit A13. It is easy to see that for each byte of points
now there will be its own attribute byte, which differs in address
more by 8192 bytes. This creates two areas of RAM:
from 1b384 to 22527 for points, and from 2457b to 30719 for attributes.
By the way, there is a gap of 2048 bytes between the areas
convenient because the TR-DOS buffer gets there, which eliminates
problems when using the disk drive. Even though
video RAM size increased from 6912 to 12288 bytes, at 3.5 MHz
It is quite possible to process the screen. On128th cars, as well as
In normal mode, it is possible to use a second screen. By the way,
someone might think that in the new mode the video controller
accesses RAM more often, and because of this, work will slow down
processor, but this is not the case. In normal mode, every time
reading a byte of points, the byte is also read
attributes, despite the fact that there is one byte of attributes
used for eight point bytes.
In conclusion, I want to say, for example, it would be possible to do
switching from normal mode to new mode by software, not by button,
or use bits 7 and 6 of the attribute byte as separate BRIGHTs
for INK and PAPER colors, but this will complicate the finalization. That's all
the advantage of this modification is that it can
any person can do it, even if he has virtually no knowledge of
"iron". Maybe this revision will allow at least something to change on
Speccy.
Completion of the computer "PENTAGON-128"
┌╥┐
vyv.8/D15(D28) ─>──────┐ ║ ║
+5V ─>─────── ║────>pin 1/D14(D32)
vyv.9/D15(D28) ─>───●──┐ ║ (tear off first)
│ ║
general(┴) ─>─●─┼─── ║────> vyv.3/D8(D8)
└─┼──┐ ║ (tear off first)
│ ║
└─── ────> vyv.11/D17(D34)
(tear off first)
Note: microcircuit numbering is given according to the most well-known scheme
(located on three A4 sheets), numbered in brackets
scheme of the company "Cervus Elaphus"
Modification of the "PROFI" computer for boards of versions 3.X
┌╥┐
vyv.9/U2b ─>───●──┐ ║
│ ║
general(┴) ─>─●─┼─── ║──●─> vyv.10/U41 (previouslytear off)
└─┼──┐ ║ └─> pin 1/U33 (tear off first)
│ ║
└─── ────> pin 11/U15 (tear off first)
Note: the numbering of microcircuits is given for the lower board, according to the diagram
company "KRAMIS" (now "CONDOR") for version 3.2
Modification of the "PROFI PLUS" computer for boards version 5.X
Modification of the "PROFI PLUS" computer for boards version 5.X
┌╥┐
vyv.5/DD14 ─>─●──┐ ║
│ ║
general (┴) ─>─┼─── ║──●─> pin 13/DD2b (tear off first)
pin 11/DD10 ─>─┼──┐ ║ └─> pin 5/DDЗЗ (tear off first)
│ ║
└─── ────> pin.b/DDS9 (tear off first)
Note: chip numbering is for the bottom board,
according to the scheme of the company "CONDOR" for version 5.0Pavel Rodionov
Share your thoughts about the article