Embedded Processors Address Peripheral Issue

The trend toward multi-core devices is well underway in PCs, but in embedded systems, there's more focus on augmenting single-core devices with an array of peripherals. As geometries shrink, the cost of adding peripherals is less of a factor, giving engineers more options to integrate more functions onto microcontrollers.

As line widths get smaller, density jumps from 5,000 gates per mm2 to 50,000 gates per mm2. That means adding a peripheral or two tacks on little size or expense.

For example, complex interconnections like Ethernet, ZigBee and PCI Express all have large protocol stacks that require a fair number of gates. But with small geometries, there's no longer a huge penalty precluding their integration even in price-sensitive applications.

"In the past, you wouldn't have thought about putting these complex interconnections on an 8-bit chip, but now you can put everything on the chip, including the code," says Ata Khan, director of product innovation, microcontroller product line, NXP Semiconductor, formerly Philips Semiconductor. That code can be stored in Flash, which is also growing in size as line widths shrink.

The trend to smaller geometries will also bring lower voltages. While that's a good thing in portable applications, it can bring challenges in many embedded applications.

"When your processor core can only handle 3V, it's difficult to deal with a 5V sensor. You've got to add pads to the processor to manage the difference," Khan says.