Atmel XMEGA processor gives 8-bit MCUs a boost

Atmel XMEGA processor gives 8-bit MCUs a boost

While some embedded system engineers want, and certainly need, 16- or 32-bit processors, others want to think small and stick with 8-bits if they can get the performance they need.

Product of the Year award winner Atmel has upped the 8-bit performance envelope for many real-time applications with its XMEGA MCU. It does so not by raw MIPS, but by clever implementations that also save power.

The XMEGA 8-bit MCU was developed by teams in Trondheim, Norway; Nantes, France; Espoo, Finland; and San Jose, California. A few of the many key team members are Ole Alexander, project manager; Terje Saether, analog design director; Stein Danielsen, project manager; and Per Olav Bringsvor, chip integration manager.

A few of the members of the XMEGA design team.

The design team saw that, in many applications, a signal on one peripheral requires a response from another peripheral, plus moving some data around. Although the CPU typically manages these activities, they do not actually need the CPU. They implemented an event system that enables interperipheral communication without CPU or DMA usage.

This ensures 100% predictable and short response time. Up to eight simultaneous events or interrupt conditions in the peripherals can automatically start actions in other peripherals. The system features a deterministic interrupt response time of 31.25 to 62.5 ns. The chip’s four-channel DMA controller enables fast CPU-independent data transfer between various combinations of data memories and peripherals. The IC also has a 2-Msample/s A/D converter and a 1-Msample/s D/A converter.

The device uses a single-cycle AVR core, has 32 general-purpose registers, and operates as low as 1.6 V at 12 MHz or 2.7 V at 32 MHz. It consumes 100 nA in sleep mode with SRAM retention, and can wake up in 5 µs. Kristian Saether, AVR marketing manager, says the XMEGA MCU has been a tremendous success right from its October 2008 introduction date.

Jim Harrison