Printed circuit board (PCB) design has come a long way since
Protel’s Easytrax first appeared. This simple yet effective DOS-based package,
along with the more advanced Autotrax, gained much popularity back in the 1980s
and they’re still in use today.
Until Protel arrived on the scene, PCB layout and most similar
EDA (Electronic Design Automation) tasks had been the exclusive domain of
UNIX-based software running on minicomputers and mainframes. This kind of
hardware was out of the question for small operations, so layouts had to be done
manually.
Manually laying out PCB designs is laborious, involving the use
of stencils, black tape and scalpel on paper or transparent sheets. As with text
from a typewriter, editing the completed output is nigh on impossible.
By attacking the problem from the designer’s viewpoint, Protel
came up with an effective system that ran on available desktop hardware and cost
a fraction of the price of high-end solutions. Later, Protel were one of the
first companies to develop EDA applications for Windows, taking advantage of
Windows’ improved memory management and user interface.
Protel 99, the latest offering, is packed with all the features
that any designer could wish for and at first sight is simply overwhelming.
There are so many features that it is just not possible for us to cover them all
in a review of reasonable length. Instead, we’ll concentrate on the key elements
and see how they work together.
Designing A Typical PCB In Protel 99
(1) Define project concept.
(2) Schematic capture – the circuit is drawn and edited.
(3) Schematic design verification – errors like floating inputs
and unconnected power pins are automatically detected.
(4) Circuit simulation (optional) – all or part of the circuit
is simulated and the results analysed to ensure that it functions as
expected.
(5) PCB layout – design information is transferred from the
Schematic Editor to the PCB Layout Editor. Components are then placed and tracks
are routed manually and/or automatically within the editor.
(6) PCB design verification – rules are applied to ensure
design integrity and manufacturing viability.
(7) Result – output files are generated ready for direct input
to the PCB manufacturing process.
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