Transcript 슬라이드 1
Low Power Sensor Node Design with MSP430 + CC2520 YoonMo Yeon 2008. 3. 26. Contents • Design Purpose • CC2520DK • Development Environment • RF Test • Current Consumption Test • Further Works • Hardware • Software Design Purpose • Battery Powered Sensor Node • Can last about 1-year • End node only • Low duty-cycle Low Power Principles • Use Interrupts to wake the processor and control program flow • Peripherals should be switched on only when needed • Minimize active duty cycle Chip Selection • CC2520 • 2.4GHz RF Transceiver • Improvements over the CC2420 • output power : 0dBm → +5dBm • min. operating voltage : 2.1V → 1.8V • low power modes (LPM1, LPM2) • MSP430F2168 • 16bit low-power MCU CC2520DK • CC2520EM • RF Module with antenna • CCMSP-EM430F2618 • MSP430F2618 core module • 14-pin JTAG • No additional IOs • SmartRF05EB • Provides various IOs & Power • USB, RS-232, LCD, LED, Switch… Development Environment • Compiler • IAR Embedded Workbench for MSP430 • JTAG • MSP430 USB-Debug-Interface Example Code : PER Test • BasicRF • Simple protocol for Tx/Rx • Not a complete data link or MAC layer • Doesn’t have full error handling • PER PER 1 (1 BER ) packet _ length PER Test Code (Tx.) • Transmitter • Sends 100 packets / sec. • 10ms Timer Interrupt • Enter LPM3 after sent one packet Timer Configuration halMcuSetLowPowerMode() PER Test Code (Rx.) • Receiver • Wait until a packet is arrive • Calculate PER & RSSI • There is no LPMs Outdoor RF Test • The KNU campus 500m 360m 260m 160m 80m 0 Test Result • -4dBm mode power is too low to communicate • At 500m distance, 10000 packets • +0dBm mode : 357/1000 (35.7%) • +4dBm mode : 47/1000 (4.7%) 76/1000(7.6%) • Varys according to moving cars and so on… Current Consumption Test • Active Current • MSP430F2618 (8MHz) : 4.7mA • CC2520 : 1.6mA • During Tx. loop in PER Test code • Max. 41.5mA • min. 3.94mA (LPM3) • min. 8mA (No LPMs) • CC2520 still remains active Problems to be solved • Sensors • How to interface CC2520DK with sensors • Design sensor circuit operating at 3.3V • or Interfacing 3.3V circuit to 5V circuit • Estimate active/stand-by current of sensors • Z-Stack • CC2520 Z-Stack is not developed yet (TIMAC 1.2.1 is available) Further Works • Study of • MSP430 Architecture & Programming • ZigBee Specification • Related Works References • Texas instruments • • • • CC2420, CC2520 Datasheet CC2520 Development Kit User’s Guide (SWRU138) CC2520 Software Examples User’s Guide (SWRU137) MSP430x241x, MSP430x261x mixed signal microcontroller(SLAS541A) • MSP430x2xx family users guide (SLAU144D) • Google Earth • KNU Campus image Q&A End of Presentation