The 'Wireless Wire': a Low-Power 2.4-GHz Solution for Embedded Control Applications

06 July 2009

Cypress Semiconductor Corp says its new CyFi™ Low-Power RF solution delivers the industry’s leading combination of reliable connectivity, power-efficiency and superior range, and is supported by the flexible PSoC® programmable system-on-chip. The solution is optimised for low-power wireless sensor networks and human-to-machine interfaces in a broad range of applications, including home and building automation, remote controls, and industrial monitoring.

Cypress Semiconductor CyFi
Cypress Semiconductor CyFi

“The CyFi solution opens significant new opportunities in the wireless embedded control market for Cypress, bringing our low-power, robust wireless technology and the versatility and integration of PSoC to a host of new applications,” said Dinesh Ramanathan, executive vice president of the Data Communication Division at Cypress.

“With drag and drop software, even novice wireless designers can start their applications in minutes.”

The solution consists of the CyFi protocol stack in PSoC Designer™ embedded design software, the selected PSoC device, and the CyFi transceiver (CYRF7936).

The solution’s interference immunity is a result of its Direct Sequence Spread Spectrum (DSSS) modulation and the agility to move to 80 channels in the 2.4-GHz band. It intelligently manages DSSS, data-rate and agility to minimise retransmissions, maximising time in sleep mode for increased power efficiency.

The CyFi solution uses DSSS modulation to encode data and allow the CyFi receiver to recover the signal when faced with interference. The solution intelligently selects a clear channel from the 80 narrow, 1 MHz channels at the transceiver’s disposal.
“No other 2.4-GHz solution combines DSSS modulation with this level of frequency agility,” said Mr. Ramanathan.

The solution can also increase power amplification to overcome interference. This dynamic adaptability to the operating environment also lends to optimising power consumption. In noise-free environments the CyFi solution communicates at 1 Mbps to minimise transfer time and leverage the ultra-low-power sleep current of 0.8 uA.

The solution automatically drops to a slower, more robust 250 kbps data rate when it detects interference, and it can increase power amplification to reduce retransmissions and return to sleep-mode faster.

CyFi transceivers are powered by PSoC devices, which can replace multiple discrete components, integrate numerous functions and can be reprogrammed at any stage of development.

Protocol stack
“The CyFi protocol stack has the smallest memory footprint of any comparable wireless solution,” said Mr. Ramanathan.

It has 8 KB in Flash for a hub and 5 KB for a node. This leaves room for additional system functionality in the controlling PSoC device.

Designers can use the compact protocol stack to build a complete wireless star-topology network with fewer peripherals and greater functionality.

The protocol stack has a network capacity of up to 250 nodes per hub, all with asynchronous, bi-directional communication.

The CyFi protocol stack offers a pre-configured, customisable PSoC firmware module that can be dropped into the PSoC Designer 5.0 integrated development environment (IDE) with no complex coding.

The 'wireless wire'
Control Engineering Europe had the opportunity to ask Sherif Hanna, Marketing Manager, Wireless Solutions of Cypress Semiconductor several questions about the new CyFi product and how it might relate to the controls industry.

QUESTION: From your perspective, what are process automation and control customers looking for in wireless networks?

These customers are looking for a “wireless wire.”

There is a certain comfort level that comes with handling and seeing a physical wire that transmits data and control signals. This is especially important for safety-critical applications.

The challenge for any wireless technology in process/control applications is wire-equivalent safety and reliability, with the added benefits of wireless; this eliminates the cost of wiring, increasing number of nodes and thus the benefit of the network, and getting into places that wires simply can't go.

QUESTION: How important is it to have a reliable solution in a wireless network? Why should a decision maker for a control system take this into consideration?

For the designers of control systems, the primary concern is literally having "control" at all times. This means knowing that data are flowing where they need to flow, when they need to, and those actions are being taken and confirmed.

Reliability then becomes a holistic problem that needs a holistic solution from any wireless network technology.

Consider an alarm that triggers the release of a safety valve that relieves liquid or gas pressure in an industrial application. That valve must absolutely work, as it needs to work once the alarm is triggered.

Attaching that valve to a wireless technology that may or may not enable it to receive the command to activate at the right time could cause loss of property, and even worse, loss of life. The wireless technology then must work every time, all the time.

QUESTION: Describe what Cypress’ CyFi offers that is unique

CyFi offers three unique features that make it truly the "wireless

1. Operation under extreme interference: no other wireless technology avoids and overcomes interference from other sources (such as Wi-Fi networks and Bluetooth phones and headsets) like CyFi does. CyFi networks constantly monitor their environment and proactively change their operating parameters, in real time, to maintain a continuous wireless link, using what we call Active Link Management.

2. Bi-directional communication: there is no such thing as "best-effort" with CyFi. Every message that is sent is confirmed. If failures are encountered then recovery mechanisms are brought to bear immediately. And if ultimately there is no way to get the message through, that too is communicated back to the system so that a secondary safety mechanism, for example, can be used.

3. Exceptional power-efficiency: While being extremely reliable, CyFi is also architected from the ground up to be a very light user of energy. Therefore, battery life for sensors for example can be up to several years on standard batteries.

QUESTION: Are there any companies with the process/control industry already considering Cypress?

Absolutely...including Honeywell and Johnson Controls [a building automation company in the U.S.A.]. CyFi-based systems are deployed in several factory installations already.

Starter kit
The kits supporting the CyFi solution include:

•The CY3271 PSoC FirstTouch Starter Kit with CyFi Low-Power RF. This is a low-cost USB thumbdrive kit including PSoC IDE software, a sense and control dashboard for data collection, a PC dongle with RF, a multifunction board, an RF expansion board with power amplifiers for long-range wireless applications, and two battery boards. Designers can also use the kit to leverage the touch-sensing, temperature-sensing, lighting-sensing and proximity sensing capabilities of PSoC devices.

•The CY3271-EXP1 Environmental Sensing Kit; this is the first of many future expansion kits to the CY3271. It enables a wireless sensor solution with pressure, humidity, temperature and ambient light sensors.

•The CY3271-RFBOARD RF Expansion Kit; this is an add-on to the CY3271 that provides two additional RF expansion and AAA battery boards—allowing further evaluation of the CyFi Low-Power RF solution.

•The CyFi Low-Power RF Development Kit (CY3210-CYFI) is a general-purpose development kit that enables prototyping and debugging of PSoC devices and CyFi transceivers. The kit includes two development boards, two PSoC modules and three CyFi modules to build wireless applications.

Starter kit availability
Cypress has introduced a PSoC FirstTouch™ Starter Kit with CyFi Low-Power RF (CY3271) for engineers to evaluate the quick prototyping and debugging of wireless systems based on the CyFi solution, along with development and expansion kits to streamline system design for beginning and expert designers.

The starter kit and other items are currently available on the Cypress Online Store at as well as in Cypress’s channel partners’ inventories.

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