Civil Engineering Reference
In-Depth Information
the processor and to cable characteristics. The period is often designated by
the clock speed of a processor.
As can be seen in Figure 2.1, the ideal voltage pulses of the data should be
the sharp step pulses. However, due to cable and processor characteristics,
the actual voltage pulses which appear in the communication cable deviate
noticeably from the ideal pulses. The data (voltage pulses) can be recognized
correctly before such deviation reaches a certain degree.
It can be considered that all information is represented in digital computers
in this way (note that data transmitted between computers can be in different
formats). The information refers to
data
,
instructions
and
addresses
, although
they have very different uses. The actual
data
,
instructions
and
addresses
are
represented by groups of
0
s and
1
s. Table 2.1 shows a comparison of some
data in decimal, binary and hexadecimal forms.
2.2 Microcomputer
2.2.1 The microprocessor
The microprocessor or central processing unit (CPU) is the principal compo-
nent both of the conventional microcomputer and the BAS control station.
It is a micro-electronic chip produced by large-scale integrated (LSI) circuit
manufacturing techniques on a small chip of silicon (about 5 cm
2
), and it is
the 'brains' of a microcomputer. More recent microprocessors are VLSI (very
large scale integrated) chips and are correspondingly more powerful. The
actual microprocessor chip is often contained in a package with a number of
pins, like legs, connecting the chip to the motherboard.
Temporary store
or registers
ALU
Control unit
Figure 2.2
Central processing unit (CPU) or microprocessor.
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