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Thursday, December 10, 2015

Can WiFi work for the Internet of Things?

By Nick Flaherty www.flaherty.co.uk

Enhanced Low-Power (ELP) Wireless MCUs Provide Multi-protocol Support and Quadruple Battery Life in Sensors

If you are Broadcom, shortly to be subsumed into Avago, then the answer seems to be no.

The launch of a family of low power devices under the WICED brand to offer low power would seem to be a route forward - after all, WICED ((Wireless Internet Connectivity for Embedded Devices) is built on Broadcom's WiFi technology. But the new CORE enhanced low power (ELP) use other technologies to achieve the power reduction.

Using low power WiFi to connect sensors for the Internet of Things is a bit of a 'holy grail' as it means that sensor nodes can be easily added to the home network. Unfortunately, the WiFI protocols suck the power from the battery. This is why Zigbee and now Bluetooth Smart (Bluetooth Low Energy 4.0 and 4.1, with 4.2 emerging soon) have emerged as viable technologies. The trouble is that Zigbee and other 802.15.4 technologies need a gateway to link the sensors to the home network (usually via WiFi). Bluetooth smart held promise as the sensors could connect directly to a smartphone but still mostly need a gateway device.

So a pin-compatible family of 802.15.4 and Bluetooth Smart devices is a great step forward, it's just not the one we hoped for.

The WICED CORE ELP Bluetooth family delivers advanced technology for a wide range of IoT applications, including simultaneous multi-protocol support, the industry's first 40nm flash memory in a communications SoC, low-power consumption and a common development platform. By integrating a host of features including increased processor speed, FPU and DSP libraries, more applications RAM and significant flash memory on a chip the size of a fingernail, Broadcom enables OEMs to create more complex applications and employ a wireless MCU that scales across a much wide product set. "Broadcom further separates itself from the competition with our new WICED CORE ELP family," said Brian Bedrosian, Senior Director of Product Marketing for Wireless Connectivity at Broadcom. "In addition to enabling multi-protocol support, we support more complex IoT applications for OEMs and developers, all while consolidating our low-power solution in a small package."
There are three different multi-protocol devices, all sharing an ARM Cortex CM4 core with floating point and digital signal processing extensions to get that lower power and enable the same software to be used across the different devices:
  • BCM20719 which supports both Bluetooth and Bluetooth Smart protocols
  • BCM20729 which supports Zigbee and 6LoWPAN protocols
  • BCM20739 which supports Bluetooth, Bluetooth Smart and IEEE 802.15.4 protocols
The family of devices supports: 
  • 512 KB RAM for complex applications
  • 1MB flash memory for program and data storage including support for over-the-air updates
  • Integrated Bluetooth and Bluetooth Smart and Zigbee 3.0 software stacks
  • Advanced sleep and latency management circuitry
  • Compliant with Bluetooth 4.2 specification
  • Expansive set of IO including precision A/D convertors
    • Support for UART, SPI, Quad-SPI and Serial Control interfaces for interfacing to external nonvolatile memories, peripheral ICs, and sensors
  • On-chip, multi-channel ADC for measuring sensor inputs, battery level, and more
  • On-chip AES 256 encryption engines with support for RSA, MD5, ECC and secure element
  • Native wireless charging support for A4WP and Airfuel
The devices are sampling now, but whether the WICED branding survives the Avago merger remains to be seen.


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