Spekutrum inside - logic elements.

<b>Spekutrum inside</b> - logic elements.

    This column is specially designed for all
fans to dig into his computer and those
who is not too friendly with a soldering iron, but still
would like to understand how it works Speccy. We do not
We give here any supercomplex
materials that are understandable only to professionals. More
Furthermore, we would like very much in their articles
focus on the newcomers in all these
technical matters. Nevertheless, we will try
that this topic was meant for all.
Here we will discuss repairs
finalization of your computer. You can also
submit articles, notes and questions on this
occasion.

    And today we're a little illuminate the structure of your
computer. Especially for those who have not yet
imagined himself as the technical genius, but for the last
We also find interesting information, but it
already in the next issue of our magazine.



        ----- Logic elements. ----


    As you know, the computer consists of
"Some" of chips, each of
which performs a specific function, but
working principle is the same. Chip
work in the binary system, ie
use only two numbers: 0 and 1. All
information is perceived only in binary form.
Unit - a signal, a zero - no signal. Zeros and
alternate units, and obtained the required
information, such as the number seven - it's 0111,
eight - 1000, etc.

    Circuit consists of logic elements
who both work with this information. Such
only three elements: a logical AND, logical
"OR" logical "NOT".

    Each chip is the most difficult - it's just
only a set of logic elements.

    Thus, the computer consists of a set
chips with different purposes, but at the same
the principle of operation. Each chip consists of
logic elements that operate in a binary
system of calculation.

    Consequently, the computer - is a huge
number of logic elements (and their
Only three species), such as
receiver consists of resistors,
transistors, diodes.

    How does it work these logic gates? Too
quite simple. Consider how each of them:

1. Logical AND - logical multiplication
(Nonyunktsiya). Designation on the structural
diagram on the left (two inputs, one output).

    Multiplication is slightly different from usual, because
made with the binary numbers: 0 * 0 = 0 1 * 0 = 0;
0 * 1 = 0 1 * 1 = 1. In words, this can be expressed as:
the presence of at least one-zero results in zero
result. Life example: You want to
self-drive, for that you need
have the machine itself, a driver's license
medical clearance to drive. If any
one of these conditions is not satisfied (zero),
what car do you drive can not (the result is
zero). If all the above listed you have
(1), then everything is in order, and one for motorists
our streets has increased (the result is
unity). This is the essence of the logical "AND".

2. Boolean "OR" - a logical disjunction
(Disjunction). Oboznachenie on structural
diagram on the left (two outputs, one input).
Rule: the presence of at-least one unit, makes
response equal to unity: 0 +0 = 0, 1 +0 = 1, 0 +1 = 1 1 +1 = 1.
Life example: You want to buy a car yellow
color. The store is the car white and yellow. You
choose yellow (1), and white leaves without
attention (0). The result is unity. If the
store has only green (0) and blue (0)
machine, then you go home sad (0 +0 = 0). And if
All cars sold yellow (1), then you are
equal to only buy one machine (1 +1 = 1). This
was a logical OR.

3. Logical "not" - the inversion.
Designation on the block diagram on the left
(One input, one output). At the output produces
the opposite meaning: 0 => 1 1 = 0. For example:
You are not satisfied with the color of your car (0) and you it
repaint your favorite color (1). If
You are satisfied with the color of your car (1), then you do 
not become a repaint (0). This here is a logical

"NO".


    On these three acts and is based job
each chip, and hence the computer.

    One of the simplest schemes is to decode
(A small part of the real chip).
The decoder is a device that selects one
signal from the set of signals. For example comes
cell address memory means to read information
from this address.

    This scheme has a total of 4 addresses (for
simplicity).



      Inputs Outputs


     X1 X2 Y1 Y2 Y3 Y4


      0 0 1 0 0 0

      1 0 0 0 1 0

      0 1 0 1 0 0

      1 1 0 0 0 1


    Hope you had fun and you all
understood.

    Let me finish on this!



               Andrew Gardeners (KANDAS), 1996



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