CYWUSB6935: WirelessUSB LR 2.4-GHz DSSS Radio SoC
•
2 gefällt mir•719 views
Introduction of the WirelessUSB technology and CYWUSB693 WirelessUSB transceiver
![CYWUSB6935: WirelessUSB LR 2.4-GHz DSSS Radio SoC ,[object Object]](https://image.slidesharecdn.com/cypresscywusb6935wirelessusblr2-4ghzdsssradiosocaudio-110310221346-phpapp02/85/cywusb6935-wirelessusb-lr-24ghz-dsss-radio-soc-1-320.jpg)
![Introduction ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Empfohlen
Weitere ähnliche Inhalte
Was ist angesagt?
Was ist angesagt? (20)
Ähnlich wie CYWUSB6935: WirelessUSB LR 2.4-GHz DSSS Radio SoC
Ähnlich wie CYWUSB6935: WirelessUSB LR 2.4-GHz DSSS Radio SoC (20)
Mehr von Premier Farnell
Mehr von Premier Farnell (20)
Kürzlich hochgeladen
Kürzlich hochgeladen (20)
CYWUSB6935: WirelessUSB LR 2.4-GHz DSSS Radio SoC
- 3. WirelessUSB Market Positioning Proprietary 27MHz/900MHz ZigBee networking solution for home/industrial automation Simple Point-to-Point wireless solution BT Short-range networking solution Long-range networking solution 802.11 Cost / Complexity Strategy:make WirelessUSB the defacto standard for multi-point to point wireless Networking Wire Replacement UWB Short-range, high-speed networking solution RFID Tags WirelessUSB TM Simple Multipoint-to-Point solution Active/Passive Tags for inventory tracking
- 9. Functional Description of CYWUSB6935 The CYWUSB6935 transceiver is a single-chip 2.4-GHz Direct Sequence Spread Spectrum (DSSS) Gaussian Frequency Shift Keying (GFSK) baseband modem radio that connects directly to a microcontroller via a simple serial peripheral interface.
- 14. 1 Bit Transmission using a 64 bit PN Code
- 16. Avoiding Interference 2400 2404 2408 2412 2420 2424 2428 2416 Close range Wi-Fi signal may interfere with your 2.4GHz device Interference detected due to increased error rates Free channel found Frequency (MHz) The key to avoiding interference is detecting it Receive Signal Strength Indicator High signal strength ( RSSI ) detected here, so search continues
- 17. Application Examples CYWUSB6935 Battery Powered Device
- 18. MCU Interface Sequence Diagrams
- 19. Application: WirelessUSB LR Alarm System WirelessUSB LR Alarm System
Hinweis der Redaktion
- Welcome to the training module on Cypress CYWUSB6935: WirelessUSB LR 2.4-GHz DSSS Radio SoC. This training module introduces the WirelessUSB technology and CYWUSB693 WirelessUSB transceiver.
- Wireless technologies have gained rapid acceptance in the marketplace and the growth continues to accelerate. The ability to move data without having to connect a cable, run wires, or worry about having the right adapters is very appealing. Wireless offers the promise of convenience, speed, and ease of use. Wireless is still all about moving information from point A to point B. Depending upon the needs of the application, data may move in one direction only, or it might need to move in both directions. There are many different wireless technologies in use or emerging today. Examples include WiFi®, Bluetooth®, ZigbeeTM, Ultra-Wide Band (UWB), and many more.
- These technologies differ in many ways, such as frequency spectrum, data rates, data encoding, protocols, network topologies, and others. The Cypress WirelessUSB and PRoC products are aimed at mid to low data rates (up to 1 Mbps) and simple cable replacement or simple network topologies. WirelessUSB only supports moving data in one direction at a time, thus it is half duplex.
- Here gives the difference between WirelseeUSB and 27MHz technology.
- Here introduces the difference between WirelseeUSB and Bluetooth technology method.
- The CYWUSB6935 provides a complete SPI-to-antenna radio modem. The CYWUSB6935 is designed to implement wireless devices operating in the worldwide 2.4-GHz Industrial, Scientific, and Medical (ISM) frequency band (2.400 GHz–2.4835 GHz). The CYWUSB6935 contains a 2.4-GHz radio transceiver, a GFSK modem, and a dual DSSS reconfigurable baseband. The radio and baseband are both code- and frequency-agile. Forty-nine spreading codes selected for optimal performance (Gold codes) are supported across 78 1-MHz channels yielding a theoretical spectral capacity of 3822 channels. The CYWUSB6935 supports a range of up to 50 meters or more.
- Here shows overall areas where this device can be used. This device will fit into more or less every areas where we require wireless connectivity with suitable Data rate. It can go into Home/Building Automation, Industrial Control, Meter Reading, Consumer applications like remote, toys, locator alarm, presenter tool, etc.
- The CYWUSB6935 transceiver is a single-chip 2.4-GHz Direct Sequence Spread Spectrum (DSSS) Gaussian Frequency Shift Keying (GFSK) baseband modem radio that connects directly to a microcontroller via a simple serial peripheral interface. As stated previously, the CYWUSB6935 contains a 2.4-GHz radio transceiver, a GFSK modem, and a dual DSSS reconfigurable baseband. The radio and baseband are both code- and frequency-agile. Forty-nine spreading codes selected for optimal performance (Gold codes) are supported across 78 1-MHz channels yielding a theoretical spectral capacity of 3822 channels. The CYWUSB6935 supports a range of up to 50 meters.
- This transmitter uses a DSP-based vector modulator to generate an accurate GFSK carrier. The receiver uses a fully integrated Frequency Modulator (FM) detector with automatic data slicer to demodulate the GFSK signal. Data is converted to DSSS chips by a digital spreader. De-spreading is performed by an oversampled correlator. The DSSS baseband cancels spurious noise and assembles properly correlated data bytes. The DSSS baseband has three operating modes: 64-chips/bit Single Channel, 32-chips/bit Single Channel, and 32-chips/bit Single Channel Dual Data Rate (DDR).
- The CYWUSB6935 provides a data Serializer/Deserializer (SERDES), which provides byte-level framing of transmit and receive data. Bytes for transmission are loaded into the SERDES and receive bytes are read from the SERDES via the SPI interface. The SERDES provides double buffering of transmit and receive data. While one byte is being transmitted by the radio the next byte can be written to the SERDES data register insuring there are no breaks in transmitted data. CYWUSB6935 has a fully synchronous SPI slave interface for connectivity to the application MCU. Configuration and byte-oriented data transfer can be performed over this interface. An interrupt is provided to trigger real time events.
- WirelessUSB LS utilizes a 2.4-GHz direct sequence spread spectrum (DSSS) radio interface. DSSS generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a “chip” or a pseudo noise code. Because they use direct sequence spread spectrum (DSSS) technology, WirelessUSB systems encode their data within Pseudo Noise (PN) codes. The main advantage is to increase the robustness and recoverability of the signal in the presence of interference. A simple explanation is that a single data bit from the application is represented by multiple bits when sent across the air, and decoded back into the original data bit on the other side. One result of using PN codes is that devices in a given network must agree to use a common PN code in order to understand one another. Another advantage of this is that it increases the co-location capabilities since devices can share the same channel if they use different PN Codes.
- The pseudo noise code is a binary signal that is produced at a much higher frequency than the data that is to be transmitted. Because it has a higher frequency, it has a large bandwidth that spreads the signal in the frequency domain. The nature of this signal makes it appear that it is random noise. The wide bandwidth provided by the pseudo noise code allows the signal power to drop below the noise threshold without losing any information. This allows DSSS signals to operate in noisy environments and reduces the interference caused by traditional narrowband signals.
- In the presence of interference, the transmitted PN code will often be received with some PN-code chips corrupted. The receivers use a data correlator to decode the incoming data stream. If the number of chip errors is less than the correlator error threshold, the data will be correctly received. Otherwise, the data bit will be marked as “unknown” and the software error recovery mechanism will be used to recover the “unknown” data. In the WirelessUSB protocol, PN Code is a one-byte number index to the gold code table. Changing the receiver’s PN Code is equivalent to changing the 32-chip or 64-chip “pattern” that the receiver is trying to look for.
- The RSSI register (Reg 0x22) returns the relative signal strength of the ON-channel signal power and can be used to determine the connection quality, determine the value of the noise floor, and check for a quiet channel before transmitting. The internal RSSI voltage is sampled through a 5-bit analog-to-digital converter (ADC). The conversion produces a 5-bit value in the RSSI register along with a valid bit. Once a connection has been established, the RSSI register can be read to determine the relative connection quality of the channel. To check for a quiet channel before transmitting, first set up receive mode properly and read the RSSI register. Then, wait greater than 50 μs and read the RSSI register again. Next, clear the Carrier Detect Register and turn the receiver OFF. A RSSI register value of 0-10 indicates a channel that is relatively quiet. A RSSI register value greater than 10 indicates the channel is probably being used. A RSSI register value greater than 28 indicates the presence of a strong signal.
- The ISM band is a busy spectrum with a lot of different technologies sharing the band. Therefore, managing interference is an important consideration. The DSSS technology itself is the first stage of managing interference. In the presence of stronger interference, the DSSS technology by itself may not be enough to overcome interference. There are another mechanism for overcoming interference. The first is detecting the interference, which can be accomplished by monitoring the background noise level using the measurement of signal strength. Once interference has been detected, the system must then identify a channel with an acceptable level of interference, and then move all nodes on the system to this new channel.
- This slide shows a block diagram example of a typical battery powered device using the CYWUSB6935 chip. The CYWUSB6935 uses the four-wire SPI to communicate with an application MCU.
- This diagram shows MCU interface with this wirelessusb device and its sequence. The four-wire SPI communications interface consists of Master Out-Slave In (MOSI), Master In-Slave Out (MISO), Serial Clock (SCK), and Slave Select (SS). The SPI receives SCK from an application MCU on the SCK pin. Data from the application MCU is shifted in on the MOSI pin. Data to the application MCU is shifted out on the MISO pin. The active-low Slave Select (SS) pin must be asserted to initiate a SPI transfer.
- This figure shows the application schematic using this device as networked connected device (i.e. one master and many slave devices connected).
- Thank you for taking the time to view this presentation on CYWUSB6935 . If you would like to learn more or go on to purchase some of these devices, you may either click on the part list link, or simple call our sales hotline. For more technical information you may either visit the Cypress site, or if you would prefer to speak to someone live, please call our hotline number, or even use our ‘live chat’ online facility.