Motorola's DSPs Bridge MCU Gap

Electronic News, April 23, 2001 by Tom Murphy

Motorola Inc. is making the world safe for DSPs yet again, especially for the developers of embedded microcontroller-based systems.

Last Wednesday, Motorola's Semiconductor Products Sector released the latest versions of it what it calls hybrid controllers that take the company's system-on-a-chip approach and combine microcontroller functionality with DSP performance on the same silicon die.

The chips, called the 56F826 and the 56F827, are designed for a variety of applications such as control and telephony. They can also help those used to designing with microcontrollers to gradually get used to DSP-based systems without taking the full plunge, according to one analyst.

Will Strauss, president of market research firm Forward Concepts Inc., Tempe, Ariz., said the 56800 series basically consists of a DSP core. But that designation presents a difficult hurdle for those used to writing code for the less math-intensive microcontroller registers.

Since Schaumburg, Ill., Motorola is still the largest vendor of microcontrollers, and since other DSP companies are aggressively targeting those end-users to switch over to DSP, Motorola took on the clever marketing strategy of providing a bridge from microcontrollers to DSPs, Strauss said.

"Many microcontroller users are migrating to DSP not because they want to, but because they have to," Strauss said. And Motorola's 56800 series allows those designers to preserve their legacy code while incorporating DSP functions.

The 56F826 part is designed for battery-operated portable systems such as PDAs or Internet-access devices, said Michael Ponzo, director of marketing for Motorola's DSP Standard Products Division. Unlike Motorola's Dragon Ball processors that have become widely successful in the Palm Pilot, the 56F826 is designed to complement the host controller and not replace it. However, it will be able to provide those PDAs with communications functions.

In comparison, the 56F827 is designed with communication interfaces and a 10-channel analog-to-digital converter for use in embedded systems in consumer appliances and industrial control, according to Sam Khoury, strategic marketing manager for the DSP Standard Products Division.

Strauss said many existing microcontroller systems rely on external sensors to tell them when to turn a motor on or off. However, with a DSP and an ADC on the MCU, the sensor can be eliminated, thereby cutting the cost and complexity of a system design.

Motorola believes that combining the functionality of an MCU and a DSP onto one device will help reduce design times for its customers and allow them to design more cost-effective solutions. The family of products comes with a package of DSP algorithms, drivers and application software to help make designing easier.