4 MB "SPECTRUM"!!
Modernization of the computer "ROBIK"
In 1989, Cherkasy NPO "ROTOR"
start of serial production of SPECTRUM
-compatible computers "Robik". Since then
4 versions of this have been released since then
cars. In practice it turned out that everything
versions were far from completely compatible
Tim with the original. Due to changed
ROM many programs using
interrupt vector I ranging from #38 to
#3B, didn't work. The reason is in the Russian sign-
generator, flashed in ROM. In addition,
for the third version, was rewritten
keyboard polling program (in view of
the presence of additional keys RUS, LAT
EDIT, DEL, etc.), which, again, went
clearly not to the benefit. The fourth version of "Ro-
Bika" generally stands apart and is
is the most unsuccessful model (disappeared
even "shadow" RAM and the ability
connect the drive). Another common
the disadvantage of all "Robiks" is
"slowness": number of cycles in
interrupt does not exceed 68000.
However, be that as it may, but "Ro-
bik", with all its shortcomings, up to
satisfied for a certain time
user tastes: convenient expandable
Remote keyboard, easy to connect
values, high reliability and abundance
programs compensated for all shortcomings.
The situation changed when, with the advent of
software for
128k, the question arose about expanding the memory.Structurally, "Robik" was created as
machine with closed architecture. Functions
VIDEO-RAM controller and controller
external ports were executed by the program
worldable logical matrices (PLM)
556RT1, 556RT2 and 155PE3 and therefore computer
yuter any modernization practically
didn't give in.
The problem with expansion to 128k was resolved
shena at the end of 1995 Cherkasy
computer studio "VG". There was once
RAM expansion scheme 48k up to
128k consisting of 10 chips
ordinary logic.
After some time it was possible to program
frame the PLM 556RT2 and at this time
ment expansion scheme includes
itself 2 MS (556RT2 and 555TM9), not counting
additional memory line from RU5.
Then, based on this development,
circuits were assembled for 256k and 512k ma-
tires on one and two RU7 lines corresponding to
responsibly.
With the advent of cheap single- and
four-megabyte SIMMs (in Cherkassy-
10$ and 25$), it became possible
It is possible to use this scheme for
RAM expansion from 256 KB to 4 MB in charge
depending on what SIMM it uses -
xia (for 256 kb you need a line of eight
RU7).
The final circuit includes 5 MS,
not counting the SIMM itself. She allows
install the above amount of RAM to
any types of Spectrum-compatible computers
terah with separate or common fields
memory.
When selecting port addressingtop
memory ports were adopted as standard
#7FFD (up to 512k Pentagon bits 6 and 7) and
#FDFD (up to 4 x MV ATM bits 0...3).
Refinement of the computer consists in
replacing RU5x with a RAM controller using
7 (A0-A6) low addresses coming from
multiplexer (555KP11) to the RAM line
and computer CAS and RAS signals. Computer
Yuters with a common memory field and RAM 128 kB
do not use signals C RU6 and A13 RU6
of this processor, and is also reduced
number of chips (one 555TM9 is needed)
and if you want to assemble a car together
I only work with Pentagon or
ATM TURBO is not needed and 555KP11.Pro-
The processor also generates control signals
AY music coprocessor (BDIR
and BC1).
All modifications are carried out using a hinged
installation and with correct assembly do not
requires adjustment. To date
more than twenty cars were assembled and
problems during assembly and operation
did not arise.
After expanding the RAM, the question arose about how
more complete compatibility with Pen-
tagon. To solve this problem
The MS controller was completely rebuilt
VIDEO-RAM K155PE3 and K556RT1. Replacing these
2 MS achieve full compatibility
bridge with Pentagon, i.e. appears
Multicolor, do not “slow down” multiple
Demo, etc.
A sore point for "ROBIK" is
and Turbo mode. As a result of the
analysis it was found that the reasonunstable operation is low speed
the growth of domestic and some im-
tailor ROMs. To reduce time
access we cut off the 20th leg of the ROM from the sig-
Nala MREQ and sit her on the ground.
In addition to this, to exclude
influence of the disk drive controller on operation
machine, a circuit is assembled, which, when
accessing the drive switches the machine
to normal mode. The circuit can be block-
change using the toggle switch.
In conclusion, I would like to read through your magazine
thank Yuri Kovalevsky for his
personal text editor. Our friends
IBMers and we believe that everything is done
professionally and for the widest
circle of consumers.
Questions can be directed to the following
my address:
257003, Ukraine, Cherkassy, Engel str.
CA 118, 2nd floor,
studio "VG".
Phones in Cherkassy: (0472) 64-33-48
15-44-44
pic 4096.C,0,0,24,32,0,5,1,1,0,0
Wiring Simm
1 - +5 v
2 - CAS 18n PT2
3 - D0
4 - A0
5 - A1
6 - D1
7 - A2
8 - A3
9 - -5 v
10 - D2
11 - A4
12 - A5
13 - D3
14 - A6
15 - A7 16n PT2
16 - D4
17 - A8 15n PT2
18 - A9 17n PT2
19 - A10 13n PT2 for 4x
megabyte SIMMa
20 - D5
21 - WE (write/read)22 - -5 v
23 - D6
24 - -
25 - D7
26 - PQ not used
27 - RAS
28 - PCAS not used
29 - PD not used
30 - +5 v
Data (D0-D7), addresses (A0-A6), signals
CAS, RAS, WE (read/write) of the same name
signals from your computer (video RAM).
turbo.C,0,0,20,23,0,5,1,1,0,0
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