【正文】 StandBy 44 260181。A StandBy 84 275181。A StandBy 124 280181。A StandBy 164 285181。A StandBy 204 300181。A Rx@433 16OFF Rx@868/915 16OFF Ma Reduced Rx 16OFF mA Tx@ 10dBm 16OFF 30 mA Tx@ 6dBm 16OFF 20 mA Tx@ 2dBm 16OFF 14 mA Tx@ 1dBm 16OFF 11 mA Conditions: VDD = , VSS = 0V, TA = 27186。C, Load capacitance of external clock = 13pF, Crystal load capacitance = 12pF PACKAGE OUTLINE nRF905 uses the QFN 32L 5x5 green package with a mat tin finish. Dimensions are in mm. Remended soldering reflow profile can be found in application note nAN40008, QFN soldering reflow guidelines, . Table 5 nRF905 package outline. Package TypeAA1A2bDEeJKLQFN32(5x5 mm)Mintyp.Max5 BSC 5 BSC BSC GLOSSARY OF TERMS Table 6 Glossary of terms.Term Description ADC Analog to Digital Converter AM Address Match CD Carrier Detect CLK Clock CRC Cyclic Redundancy Check DR Data Ready GFSK Gaussian Frequency Shift Keying ISM IndustrialScientificMedical kSPS kilo Samples per Second MCU Micro Controller Unit PWR_DWN Power Down PWR_UP Power Up RX Receive SPI Serial Programmable Interface CSN SPI Chip Select Not MISO SPI Master In Slave Out MOSI SPI Master Out Slave In SCK SPI Serial Clock SPS Samples per Second STBY Standby TRX_EN Transmit/Receive Enable TX Transmit TX_EN Transmit Enable MODES OF OPERATION The nRF905 has two active (RX/TX) modes and two powersaving modes Active Modes ? ShockBurst? RX ? ShockBurst? TX Power Saving Modes ? Power down and SPI programming ? Standby and SPI programming The nRF905 mode is decided by the settings of TRX_CE, TX_EN and d PWR_UP. nRF ShockBurst? Mode The nRF905 uses the Nordic Semiconductor ASA ShockBurst? feature. ShockBurst ?makes it possible to use the high data rate offered by the nRF905 without the need of a costly, highspeed micro controller (MCU) for data processing/clock recovery. By placing all high speed signal processing related to RF protocol onchip, the nRF905 offers the application micro controller a simple SPI interface, the data rate is decided by the interfacespeed the micro controller itself sets up. By allowing the digital part of the application to run at low speed, while maximizing the data rate on the RF link, the nRF905 ShockBurst? mode reduces the average current consumption in applications. In ShockBurst ? RX, Address Match (AM) and Data Ready (DR) notifies the MCU when a valid address and payload is received respectively. In ShockBurst TX, the nRF905 automatically generates preamble and CRC. Data Ready (DR) notifies the MCU that the transmission is pleted. All together, this means reduced memory demand in the MCU resulting in a low cost MCU, as well as reduced software development time. Typical ShockBurst ?TX: 1. When the application MCU has data for a remote node, the address of the receiving node (TXaddress) and payload data (TXpayload) are clocked into nRF905 via the SPI interface. The application protocol or MCU sets the speed of the interface. 2. MCU sets TRX_CE and TX_EN high, this activates a nRF905 ShockBurst? transmission. 3. nRF905 ShockBurst?: ? Radio is automatically powered up. ? Data packet is pleted (preamble added, CRC calculated). ? Data packet is transmitted (100kbps, GFSK, Manchesterencoded). ? Data Ready is set high when transmission is pleted. 4. If AUTO_RETRAN is set high, the nRF905 continuously retransmits the packet until TRX_CE is set low. 5. When TRX_CE is set low, the nRF905 finishes transmitting the outgoing packet and then sets itself into standby mode. If TX_EN is set low while TRX_CE is kept high, the nRF905 finishes transmitting the outgoing packet and then enter RXmode in the channel already programmed in the RFCONFIG register. The ShockBurst? mode ensures that a transmitted packet that has started always finishes regardless of what TRX_EN and TX_EN is set to during transmission. The new mode is activated when the transmission is pleted. Please see subsequent chapters for detailed timing For test purposes such as antenna tuning and measuring output power it is possible to set the transmitter so that a constant carrier is produced. To do this TRX_CE must be maintained high instead of being pulsed. In addition Auto Retransmit should be switched off. After the burst of data has been sent then the device will continue to send the unmodulated carrier. Typical ShockBurst ?RX: 1. ShockBurst ?RX is selected by setting TRX_CE high and TX_EN low. 2. After 650181。s nRF905 is monitoring the air for ining munication. 3. When the nRF905 senses a carrier at the receiving frequency, Carrier Detect (CD) pin is set high. 4. When a valid address is received, Address Match (AM) pin is set high. 5. When a valid packet has been received (correct CRC found), nRF905 removes the preamble, address and CRC bits, and the Data Ready (DR) pin is set high. 6. MCU sets the TRX_CE low to enter standby mode (low current mode). 7. MCU can clock out the payload data at a suitable rate via the SPI interface. 8. When all payload data is retrieved, nRF905 sets Data Ready (DR) and Address Match (AM) low again. 9. The chip is now ready for entering ShockBurst ?RX, ShockBurst ?TX or power down mode. If TX_EN is set high while TRX_CE is kept high, the nRF905 would enter ShockBurst?TX and start a transmission according to the present contents in the SPIregisters. If TRX_CE or TX_EN is changed during an ining packet, the nRF905 changes mode immediately and the packet is lost. However, if the MCU is sensing the Address Match (AM) pin, it knows when the chip is receiving an ining packet and can therefore decide whether to wait for the Data Ready (DR) signal or enter a different mode. To avoid spurious address matches it is remende