Hard Group - characteristics of the KAY-1024 computer.

Hhere are fragments of articles from the magazine
la "Radio amateur" and characteristics of the
nutera KAY-1024.
────────────── ────────────────────────────

KCOMPUTER KAY-256

g.S.-Petersburg (C) NEMO

The KAY-256 computer belongs to the Spectrum-se-
family and developed by NEMO (St.
-Petersburg), which has experience in their development and
production.


  WHY SPECTRUM?

Many of those who read these lines
are faced with the problem of choosing their brand
first computer.  Talk about what
Spectrun is dead, Spectrum is obsolete, etc.
It's been going on for several years now.  However,
manufacturers still produce, and
users purchase "outdated" ma-
tires. The fact is that it is still simply
purchasing a more advanced type of computer
it is impossible to achieve new quality.  Tre-
painstaking work is required to master the new
type of equipment: up to six months of personal costs
a lot of time and effort, not to mention the math
real costs. This is due to the change
niyainformal social circle and search
new ways to "extract" information, software,
forest", technical support, etc.

Atari and Commodo computer users
re, with fantastic technical
characteristics, are not able to realistically
call their potential due to information
"vacuum". Established domestic market
household computers and its infrastructure
focused primarily on Spectrum and
practically do not support other industries
line models. Volumes of available branded
th software on Spectrum
far exceed the total volume of software of all
other amateur radio computers together
those taken.

A few words should be said about the IBM PC.
For entertainment purposes, buy such an expensive
This "toy" hardly makes sense.  Here
Sega or Dandy would be more suitable.  How so far-
calls practice, home IBM is usually dub-
Liters the computer installed at work
and is used primarily in commercial
and production purposes.  In many respects
solutions (preparation of texts, etc.) more
the cheap Spectrum can replace the IBM PC.

Speaking about the prospects of Spectrum, not
We should also forget about such a concept as
inertia of the user market, which
St. Petersburg is estimated at
six months to a year. And this is for computers alone
type, having full software co-
compatible with each other and almost half-
noah withinSpectrum series.  Even
subject to the triumphal march of Commodo-
re (as it happened, for example, in the Baltic
tic republics) it can be assumed that
they will not reach the Russian hinterland soon
her than in two or three years.

  DEVELOPMENT IDEOLOGY

In the process of working on the design, we determine
The following approaches have emerged that allow
offer it as a mass household
of your computer.

1. Spectrum compatible machine with open
architecture. The decisive factor in the choice is
The amount of available software varies. Any device-
expansion of the main board depreciation
is determined by the uniqueness of its software. Therefore appa-
Only Spectrum-architecture is implemented differently.
tour, and specific tasks of specific
user groups can be decided according to
the power of peripheral devices, the convenience
connections to which sufficient attention has been given
attention. The concept of "system channel" is defined
divided in the form of a three-dimensional system bus
slot layout.

Possible peripherals are divided into two classes:

a) fast - installed on the system
bus in the form of slots inside the case;
b) slow - connected via a loop
as a separate structural volume from the outside
housing (via bidirectional parallel-
nal port).

This made it possible to avoid buffering
tires and make it more predictable and
simple.

2. Quite a large amount of RAM (256kB)
immediately placed on the main board, since
increasing the amount of RAM during operation
tation is associated with a number of technical difficulties
tey.

3. Use of existing standards for
connectors and signal levels.  Interface
peripherals compatible with
CENTRONICS, made according to the IBM PC standard
(Canon DB-25S connector).   Prototype
system bus served as a system connector
branded computer. Signal parameters
controlling the TV (monitor), in general
Newly comply with TV standard.

4. Ensure good reproducibility,
manufacturability and reliability
products at minimal cost. Se-
cost is minimized for the computer
in general, and not just for the main board,
as was done by most developers
kov earlier.  The fee is calculated for installation
into the Corvette body. PCB layout
design made by Vladimir Korovichev
(KVA).

5. Initially, the goal was not to obtain
100% software compatibility with the company
exchangeable ZX-Spectrum.  It was decided not to
plug in the FFh port, since there are no design
it does not perform any other functions (with the exception of
test for self-presence). Cro-
In addition, quite rough is used
address decryption.

           "Radio Amateur", No. 11, 1994

  CHARACTERISTICS OF KAY-1024
 Table 1
────────────── ────────────────────────────
Klayout: slot, for housing type
"system unit"
────────────── ────────────────────────────
Aarchitecture: open, bus Spectrum-
-machine
────────────── ────────────────────────────
Knumber of slots: 3 pcs., Nemo-bus
────────────── ────────────────────────────
Pprogram compatibility: 97%
────────────── ────────────────────────────
Ooperating systems:

inbuilt - SpЧ8/Sp128; TR-DOS v.5.04T;
zdownloadable - CP/M v.2.2; IS-DOS;
────────────── ────────────────────────────
ORAM capacity: 1024 kB (including quasi-disk)
────────────── ────────────────────────────
OROM capacity: 64 kB
────────────── ────────────────────────────
Djoysticks: Kempston Joystick 1 (built-in
inkeyboard block)
────────────── ────────────────────────────
ANDprinter interface: Centronics, built into
PStorage, access on channel #3 in Sp128 mode
────────────── ────────────────────────────
Mmusic processor: AY8910
────────────── ────────────────────────────
Pconnector-port for connecting external
ydevices:

-8 buffered lines;
-5 output lines of OK type;-8 bidirectional lines
────────────── ────────────────────────────
UTurbo mode control:

-OUT to port;
-logical level on the bus;
-switching on the false panel
────────────── ────────────────────────────
Tacting frequency: 3.5/NO WAIT/7.0 MHz
────────────── ────────────────────────────
KROM/RAM turbo coefficient: 2.0/1.75
────────────── ────────────────────────────

The board is designed for installation in a case from
PC "Corvette". The connectors are brought out to the front
the false panel of the computer.

The board is equipped with a disk controller
yes with full digital PLL and turbo position
alignment of heads. Installing the controller
The drive does not require any modifications.

  Passport sheet KAY-1024/ЗSL/TURBO

КDISK DRIVE TROLLER
DFOR COMPUTER KAY-256

g.S.-Petersburg (C) NEMO

The drive controller was designed with
based on the same considerations that formed the basis
computer KAY-256. Like a computer, it
is a synchronous digital auto-
tomato, which makes it possible to give a beech-
the main meaning of the expression: “Collected from is-
The device does not need the right parts
"establishing"

The special feature of the controller is that
it is designed for installation in a motherboard
KAY-256 and, thanks to the developed computer bus,
tera, has a simplified design. This is
mu its connection to other Spectrum machines
we may face a number of difficulties.

The controller architecture is significantly simplified
puppy in accordance with the prevailing
market standards. The controller also has
there are chains that duplicate similar ones in
computer.  There is no circuitry
FDC chip protection by feed order
and the presence of supply voltages.  These functions
tions are performed by the built-in conversion
lem +5/+12V in the computer.

The controller has the following differences from the pro-
totype (Beta-Disk Interface):

-only two displays are supported by hardware
driver;
-recording density control (MFM/FM) is not
implemented;
-no systemswitch, yes
how its installation entails additional
detailed design and layout samples
lems;
-bit D4 of configuration port 7FFDh fixed
communicated in the computer (RS signal);
-strobe of the moment of SOS/DOS transition
carried out by the WAIT signal;
-there is no separate clock generator;
this is a beautiful circuit design,
allowing you to get 8 MHz from the serial
frequency 14 MHz (signal F), detailed description
sano in the article: Ivanov A. Application of electrical
ment "exclusive OR" // Radio, 2, 1985
-implemented digital phase synchronizer
reading, first used in computer
terah "Search"; in amateur radio circles
this circuit design is known as a "PLL"
although in reality it is not;  in the magazine
"Radio amateur" the name "mic-
roprogrammatic data extraction machine",
which is also far from the essence of the circuit design.

The implemented PLL system significantly
increases the reliability of information reading
from the drive.  System efficiency is higher
with comparable circuitry costs
than, for example, multi-stage circuits
write precompensation.

Unlike the “classical” “PLL” “Search”
ka", which has 5 different reactions to disturbances
tion (arrival of reading pulse), given
This scheme has four of them.

The controller uses accelerated positioning
oning of the drive heads, reaching -
by increasing the clock frequency of the crystal
FDC ontime for switching on the positioning mode
vaniya. This reduces acoustic noise when
work and slightly reduces access time
to disk.

Layout of the printed connector to the floppy drive
contact matches with a similar connector
drive.  Use of prescribed
OK line standard allows switching
enable devices on the interface when turned on
power supply and hold any of the devices
(computer or disk drive) without power, not
fearing failure of the interface ICs.

The controller uses enough components
scarce IC 555IMb, but this is the most
acceptable option compared to two al-
alternative: using 556 series ICs
with fusible jumpers or “openwork” circuit
motor technology based on low-integration ICs,
significantly complicating the design. Because of
stringent requirements for micro-processing speed
circuits of the 531 series cannot be replaced with others
recommended. More details on
TRDOS system can be obtained in the book:

Larchenko A.A., Rodionov.Yu. ZX-Spectrum &
TR-DOS for users and programmers.
Ed. 3rd, rev. and additional  - St. Petersburg: Peter,
1994

A number of articles on this topic have been published in
magazine "Radio Amateur":

No. 2, 1993, No. 9, 1994

       Magazine "Radio Amateur", No. 3, 1995.

KOTROLLER PC XT KEYBOARDS
DFOR COMPUTER KAY-256

g.S.-Petersburg (C) NEMO

The controller is a complete peripheral-
device that connects to
computer system bus KAY-256 by
installation into the connector. The actual keyboard
should work in the XT standard.  Possibly
using the XT/AT keyboard, while
the switch should be set to mode
"XT".

Current consumption by the device is 0.2A;  cla-
viatura - usually up to 0.25A.  Board size
controller - 113.5 * 61.5 mm.

The controller can be connected to any
Spectrum, but will require a connection
to the internal circuits of the computer and without correspondence
appropriate qualifications to do this is not re-
recommended.

The advantage of this device can be considered
make it possible to alternately work with
keyboard and Sinclair joystick without it
shutdowns.

       Magazine "Radio Amateur", No. 5, 1995.


The XT-KLAVA controller allows the use of
install a standard IBM keyboard on your
Spectrum-e. Unlike analogues, con-
The troller is a bus device, sub-
which is connected to the terminals
Z80 CPU.  When installing the board into a computer
KAY-256 does not require any modifications.

The main keyboard field corresponds to
standard Spectrum keyboard. Service
the keys have the following correspondences:
────────────── ──────┬─────────────────────
 IBM                │        Spectrum
────────────────────┼─────────────────────
         │        
 +<1>   │        табуляция
 ++ │        сброс
              │        
             │        
         │        забой
────────────────────┴─────────────────────

                     Лист-паспорт XT-KLAVA

Фирмой Nemo гарантируется  ремонт контрол-
леров дисковода и  XT-клавиатуры  по  цене
вышедших из строя деталей в течении 6  ме-
сяцев. Иногородним покупателям,  приобрет-
шим продукцию по предварительному  заказу,
предоставляется скидка.

Приглашаются к сотрудничеству  организации
и частные лица, занимающиеся оптовыми пос-
тавками комплектующих изделий.

Поissues of purchasing boards and supplies
components please contact:

St. Petersburg (812) 159-55-69

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