SWRA578B October   2017  – April 2020 CC1312PSIP , CC1312R , CC1314R10 , CC1352P , CC1352P7 , CC1352R , CC2620 , CC2630 , CC2640 , CC2640R2F-Q1 , CC2642R , CC2642R-Q1 , CC2650MODA , CC2652P , CC2652R , CC2652R7 , CC2652RB , CC2652RSIP

 

  1.   Ultra-Low Power Sensing Applications With CC13x2/CC26x2
    1.     Trademarks
    2. 1 Overview
    3. 2 Measurement Conditions
      1. 2.1 Software
      2. 2.2 Hardware
    4. 3 Measurements
      1. 3.1 BOOSTXL-ULPSENSE
        1. 3.1.1 Analog Light Sensor
        2. 3.1.2 Capacitive Touch
        3. 3.1.3 LC Flow Meter
        4. 3.1.4 Potentiometer
        5. 3.1.5 Reed Switch
        6. 3.1.6 SPI Accelerometer
      2. 3.2 LPSTK-CC1352R
        1. 3.2.1 I2C Light Sensor
        2. 3.2.2 I2C Temperature and Humidity Sensor
        3. 3.2.3 SPI Accelerometer
        4. 3.2.4 Hall Effect Sensor
      3. 3.3 Comparison with System CPU
        1. 3.3.1 4 MHz SPI Transfer
        2. 3.3.2 1 MHz SPI Transfer
        3. 3.3.3 Wake-up and Sleep
    5. 4 Summary
    6. 5 References
  2.   A Creating the comparison examples
    1.     A.1 SPI Transfer – Sensor Controller
    2.     A.2 SPI Transfer – System CPU
    3.     A.3 Wake Up and Sleep – Sensor Controller
    4.     A.4 Wake up and Sleep – System CPU
  3.   Revision History

3.1.5 Reed Switch

The Reed Switch is capable of detecting magnetic fields. Normally, the switch is open, but when a magnetic field is applied to the switch it closes. The Reed Switch is connected in series with a pull-up resistor.

The reed switch example is tested with both a magnet present and without a magnet present. The magnet is placed directly above the reed switch. This examples wakes up with a frequency of 64 Hz. If a change in the state from last time is detected, the System CPU is woken up and alerted. Depending on the state of the reed switch, one of two LEDs will light up.

Average Current Consumption Unit
Without magnet present (64 Hz) 1.3 µA
With magnet present (64 Hz) 1.4 µA
4_1_5 Reed wMagnet.pngFigure 10. Reed Switch: Single Measurement