1. ATmega128RFA1 Power Measurement

2. ATmega128RFA1 SoC (uC and Transceiver) Up to 16 MHz (i.e. almost 16 MIPS) Voltage range: 1.8v to 3.6v 16K bytes RAM 128 K Flash Zigbee compliant transceiver

3. ATmega128RFA1 Transceiver – TX Power up to 3.5 dBm (2.24 mW) – Speed -> 250 kb/s and 500 kb/s, 1 Mb/s, 2 Mb/s – Security -> AES (128 bits) – RX current -> 12.5 mA – TX current -> 14.5 mA (max output power)

4. Power Control Features Power Reduction Registers – PRR0 (TWI, Timers, etc) – PRR1 (one bit to shutdown transceiver) – PRR2 (for disabling the four SRAM blocks) Watchdog Timer Brown-Out detect (BOD)

5. Important Peripherals Timers ADC TWI (I2C) -> RTC wake up WDT (wakeup or reliability enhancement) Transceiver

6. Sleep Current Power down mode (deep sleep) All peripherals disabled – PRR0 = 0xFF – PRR1 = 0xFF WDT enabled Current = 800 nA

7. Sense & Send: Cycle Time 3.44 ms

8. Sense & Send: TX Time 1.68 ms

9. Sense & Send: Sense Current 4.2 mA

10. Sense & Send: TX Current 15.6 mA

11. Life Time Estimate Ampere Hour – Sense -> 2.05 x 10 -6 mAH – Tx -> 7.28 x 10 -6 mAH – Total (sense & send) -> 9.33 x 10 -6 mAH In ‘one hour’ – # of Tx -> 450 – Sense & Send -> 4.1985 x 10 -3 mAH – Sleep -> 2.88 x 10 -6 mAH – Total (sense, send & sleep) -> 4.2 x 10 -3 mAH

12. Life Time Estimate For a battery of 200 mAH – # of hours we get is 200/4.2 x 10 -3 i.e. 47619 hrs or about 5 years

13. Additional Possible Optimization Frequency scaling – Static – Dynamic Use of Real-Time Clock – Keep watchdog timer disabled in sleep mode RTC chip takes less current than the WDT – Wake up on RTC alarm interrupt More flexible (not just max of 8 sec)