Design choices

Any salesperson skilled in the art of persuasion will try to convince you that you need something you may not have even considered before. Perhaps there is some merit to tacking on such extras, but at the very least they should be scrutinized before a decision is made. Helping you-the engineer-make an informed design decision is the thrust of this week's In Focus section.

For the past year or so, chip makers have been telling us that the shift to 32-bit design for embedded systems is imminent. Naturally, we're a little skeptical, considering that embedded designers are a pretty conservative bunch. But we've been hearing the same message so often that we decided to ask a few of the vendors to make their case on these pages.

Many of the benefits of moving from, say, an 8-bit microcontroller design to a 32-bit design are fairly straightforward. Raw processing performance goes up. There are more memory resources to tap. You can count on getting more-useful peripherals and communications interfaces. The list goes on.

But what about the pitfalls, such as code compatibility, new board design and hardware/software partitioning? How do you justify paying more for an off-the-shelf 32-bit MCU knowing that nothing is stopping your main competitor from choosing the same part?

It's clear the authors have heard these gripes before. All work to make a strong business case for 32 bits, from which we infer that lots of 8-bit customers are raising questions. Nevertheless, Triscend's Geir Kjosavik maintains that 32-bit MCUs based on standard CPUs like ARM will prove to be the true heir to 8 bits, leapfrogging 16-bit controllers. And Motorola's Kevin Klein argues that managers should simply stop listening to ASIC-biased engineers, switch to standard controllers and get the product out the door.

Others say chip vendors ought to shoulder some of the burden. Steve Ikei of NEC Electronics America thinks MCUs should be made to accommodate the user's software, not the other way around. Chip vendors should also be counted on to make some best-practice recommendations, as Tim Dry of Renesas does in an article about designing engine control units.