Low-Power Chip, Module Brings Wi-Fi To New Portable Apps

Nov 3, 2008 12:24 PM, By Louis E. Frenzel, Editor in Chief

Wi-Fi, also known as IEEE 802.11, is a great wireless technology and standard. But so far, it has been used primarily in fixed and mobile applications like laptops and even some cell phones where significant power is available. Now, G2 Microsystems offers a low-power system-on-a-chip (SoC) and related module that enables Wi-Fi to be used in a wider range of applications that use smaller batteries, like remote controls and asset tracking tags.

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The G2C547 is a full 802.11b/g-compatible radio media access controller (MAC) and physical layer (PHY) on a chip, though it also has its own 32-bit CPU (a version of SPARC), memory, and some very interesting I/O (Figure 1). The memory is 128 kbytes of RAM and 512 kbytes of ROM, with a 2-kbyte battery-backup ROM. The I/O consists of external flash, UART, GPIO, SDIO, and SPI, both master and slave.

Unlike most Wi-Fi chips, the G2C547 also includes a collection of sensor interface circuits, including analog-to-digital converters (ADCs), for temperature, motion, security seals, and other uses. For a low-power IC like this, the on-chip regulators and power-management circuits are a given. For many applications, no additional processor is needed. However, the chip will work with an external 8- or 16-bit controller as required.

This chip is loaded with additional features. Full crypto hardware covers AES-128, RC4, MD5, SHA-1, and CRC-32. The complete 802.11i security features are implemented for WEP and all versions of WPA. In addition, the eCos operating system (OS) running on the processor includes the complete TCP/IP stack and drivers, making Internet connectivity easy to implement.

A real-time clock makes for wakeup and time-stamp functions as well as a super-fast boot. It goes from sleep to active in 5 ms. Also, a WPA3-PSK network connection can be made in less than 35 ms. Name another Wi-Fi chip that can do that.

And that’s not all. The G2C547 offers features that make it useful in a wide range of asset tracking and other tagging applications. It includes circuitry to implement real-time location systems (RTLS). Also, it boasts a complete ISO 24730-2 real-time location transmitter and 125-kHz receiver, which are normally used in a variety of RFID applications. Further, the device supports the EPC Gen 2 900 MHz RFID standard.

With its ISO 24730-2 time distance of arrival (TDOA) location technology, the G2C547 can be used in a variety of asset tracking and location schemes. With such low power consumption, it can be used to implement much more sophisticated and accurate location systems for major assets, such as keeping track of equipment in a hospital. All of these applications can use the existing Wi-Fi access points to implement an enormous range of location services. With in-place infrastructure and this chip, designers can assemble a flexible tracking system at a very reasonable cost and time of implementation.

The chip comes in a 10- by 10-mm, 72-pin quad flat no-lead (QFN) package and works from –40°C to 85°C. Typical power-consumption figures are 10 µW in sleep/standby mode, 79 µW in listen mode, and 117 µW in active orthogonal frequency-division multiplexing (OFDM) receive mode.

If you aren’t a wireless wiz, you can also get the G2M5477 module. It uses the G2C547 chip plus a +20-dBm power amp and antenna, crystal, and other discretes to create a final working product. The module is already FCC- and CE-certified and tested for Wi-Fi Alliance apps like Wireless MultiMedia. Just drop it right into your product and go.

Two new software products for these products are also now ready for purchase. The Icon software provides Internet connectivity for any 8- or 16-bit microcontroller by offering a full Wi-Fi and networking slave for any other device. The Recon software offers telemetry application features that provide reports about temperature, pushbutton status, and motion sensors over a Wi-Fi connected Internet.

The G2 chip and modules bring new possibilities to Wi-Fi that were impractical before. The chip will compete with other wireless technologies like Bluetooth, ZigBee, RFID, and some industrial-scientific-medical (ISM) band products. The ability to take advantage of an existing Wi-Fi local-area network (LAN) makes the applications for more powerful and gives them full Internet connectivity.

The G2C547 SoC is sampling today. Initial pricing is $9 in 100,000-unit quantities. A development evaluation board, software, and other accessories are also available. The G2M5477 module sells for $22 in 10,000-unit quantities. High-volume production is planned for February 2009.