4.5 Power Consumption Results
The power consumption data of ATxmega256A3BU MCU is captured while the sensor node
is operating in active mode as well as in power down mode. The measurement setup for
power consumption consists of:
- XMEGA-A3BU Xplained
- Multimeter for current measurement
| MCU | ATxmega256A3BU |
|---|---|
| Operating Voltage | 3.3V |
| Operating Frequency | 48 MHz/4 = 12 MHz |
| CPU clock configuration | 32 MHz internal oscillator calibrated to DFLL 48 MHz, prescaled to 12 MHz |
| Sleep mode | Power down |
| Peripherals enabled | ADC, RTC32, Timer0, UART, USB, Event System, DMA |
| ADC configuration | Operates with 12 MHz system clock, signed mode, 12-bit resolution, 1 MHz sampling rate, VCC/1.6 reference voltage, timer triggers over event system |
| ADC channels | Channel 0: Temperature sensor, Channel 1: Light sensor |
| RTC32 configuration | An external 32 kHz crystal is the clock source. RTC ticks for every one minute, interrupt on overflow |
| Timer0 configuration | The clock source is a 12 MHz system clock, timer overflow interrupt occurs for every 1 ms |
| UART configuration | Asynchronous mode, 9600 baud rate, 8 data bits, 1 stop bit |
| USB configuration | 48 MHz DFLL is clock source. USB 2.0 full speed mode, CDC Class |
| Event System configuration | Clock source is 12 MHz system clock, Ch-0 of the event system is used for timer0 interrupt |
| DMA configuration | Two DMA channels to transfer data from the two ADC channels to data buffer |
Table 4-3 shows the operating conditions of the ATxmega256A3BU MCU and the list of peripherals configured for sensor node operation.
Table 4-4 shows the power consumption values of the ATxmega256A3BU MCU with different sleep period values.
| S. No. | Active Period [sec] | Active Current [mA] | Sleep Period [sec] | Sleep Current [µA] | Average Current [µA] |
|---|---|---|---|---|---|
| 1 | 4 | 9.58 | 60 | 1.1 | 599.7 |
| 2 | 4 | 9.58 | 300 | 1.1 | 127.1 |
| 3 | 4 | 9.58 | 600 | 1.1 | 64.5 |
| 4 | 4 | 9.58 | 900 | 1.1 | 43.5 |
| 5 | 4 | 9.58 | 1800 | 1.1 | 22.3 |
| 6 | 4 | 9.58 | 3600 | 1.1 | 11.7 |
The power consumption of the RN2483 LoRa technology mote in active mode is 3.76 mA and in sleep mode it is 0.87 mA.
Note:
- In this application, the RN2483 LoRa transceiver module alone is enabled on the RN2483 LoRa technology mote board. The on-board LCD display, sensors, and PIC MCU are isolated from the sensor node circuitry.