Hooked Up: Motorola's microcontroller has all the
hooks for Ethernet, so complete connections can be only a bit larger than
Ethernet is gaining acceptance in the industrial world, providing links
between the front office and factory floor equipment. Motorola's chip
subsidiary, Freescale, is bringing higher speeds to this market, unveiling a
single-chip microcontroller that runs at up to 100 Mbit/sec.
Ethernet is beginning what many feel will be a rapid ramp in factory applications as prices come down and the need for connectivity rises. The Arc Advisory Group predicts that shipments of industrial Ethernet devices will soar from only 269,000 nodes in 2002 to more than 6 million nodes in 2007.
Observers note that the usage of Ethernet is driven by the global push for standard network connections. "The driving factor is not Ethernet itself, but that it's a way to get Internet and enterprise connectivity," says Katherine Voss, executive director of ODVA, an association in Ann Arbor, MI, that focuses on networking in the factory.
While performance may not be the main factor, most observers feel that industrial Ethernet applications will mainly employ the higher-speed versions, which are becoming the norm in offices. Though data traffic won't be as high as in offices, industrial applications will benefit from the tenfold speed enhancement of traditional Ethernet devices. "Many want to have latency that's as low as possible. A few milliseconds can make a difference," says Nigel Allison, IP manager at Freescale Semiconductor Inc.
Freescale's MC9S12NE64 is a 16-bit device that provides all the functions needed for Ethernet connections, so board space requirements for the 80- or 112-pin devices are minimal. The chips house 64 kbytes of flash, Ethernet functions, a 16-bit timer and Motorola's HCS12 core. A clock generation module has phased lock loop while two serial communication interfaces and a serial peripheral interface are also available.
The compact size allows linking remote devices such as security cameras to the main network. To help in setup, the chip houses a miniature logic analyzer that lets engineers watch sequencing and data flow.
The chip is designed for rugged environments. The flash memory, often one of the most fragile technologies, uses the same processes used for Freescale's automotive devices, which have high temperature specifications. The parts will start at $9 in 10,000 lot orders.
While Ethernet will have a major role in factories, it may not displace fieldbuses such as DeviceNet and Profibus. Those architectures have small files and minimal header information, so they can be sent quickly. Ethernet files have comparatively large headers, which can slow transmission. "In controls, it's not the amount of data you send that's important, it's the time it takes to send it," Voss says.