Page 32 - Embedded Microprocessor Systems Real World Design

good development tools and other features that will minimize engineering time
required to develop the product.

Operator Training/Competence
Operator training/competence has an impact on processor selection because it
affects the user interface. If you have a product with a fairly complex set of features
and poorly trained operators (such as consumers using VCRs) , then you may need
a more sophisticated user interface. In some cases, you may need an LCD display
and touch screen. This implies more processor horsepower and memory to store
the screens and messages.
If the operators of your instrument are well trained, you may be able to use a
less sophisticated interface. For example, an electrical engineer using an oscillo-
scope probably knows what horizontal and vertical resolution knobs are for and
doesn’t need an explanation for them. If the same instrument has a sophisticated
math function with non-obvious controls, you may need the capability to display a
menu or even a help screen for the user.

The “Real” Requirements

Sometimes you must look past the request for a specific feature to get at the real
requirement. Some years ago, I worked on a product that was going to be designed
as a replacement for a current product. In looking at the requirements for the new
product, we found some users requesting easier access to change certain chemicals
stored in the machine. Looking deeper, we found that the real problem was the
capacity of the chemical storage. The only reason that users were requesting easier
access was because they had to replace the chemicals too often. Providing addi-
tional capacity solved the real problem.

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Development Environment

To develop applications on a microprocessor, some basic tools are essential:
A development system or crosscompiler
A PROM programmer
Debug hardware

In the prehistoric days of embedded systems (before the IBM PC), the standard
development system consisted of a computer from the company that sold the micro-
processor ICs and a PROM programmer. The development systems were expensive,
slow, and limited to developing software only for that manufacturer’s parts. Some
third-party companies had development systems as well. These also were expensive

System Design 17