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I/O FOR EMBEDDED CONTROLLERS

Part 1: Digital I/O
by Bob Perrin

Start ı Digital Inputs ı Protecting the Digital Inputs ı Digital Outputs ı Bridging the Gap ı Wait One, Over ı Sources and PDF

Designing generic embedded controllers is as much of an art as it is a science. Every company Iıve worked for has attempted to spin a controller board that could be reused in future projects. These companies range from a scientific research instrumentation company to a company that built wafer-handling tools VLSI fabs. These efforts have met with varying degrees of success.

Currently, I work for a company that makes C-programmable embedded controllers. Designing commercially successful generic controllers is an interesting problem. You have to try to predict your customerıs applications and deduce their I/O requirementsıno meager task.

If you work for a company that wants to develop an embedded controller as a base for current and future products, youıre lucky. This type of project is just plain fun.

Being intimately familiar with your companyıs product line will help you predict what type of applications the controller will be applied to. Knowing this, you should be able to make some educated guesses about the I/O mix youıll need.

The I/O circuits presented here have shown themselves to be useful in a wide variety of applications. The next time you have to design I/O for your firmıs embedded controller project, perhaps one or more of the circuits or ideas presented here will be of use.

In Part 1 I focus on digital techniques, and the next installment will address analog signal conditioning, A/D conversion, and D/A conversion.

NEXT

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