SLAAEN0 September   2024 MSPM0L1227 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L2227 , MSPM0L2228 , MSPM0L2228-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Low-Frequency Subsystem Introduction
    1. 2.1 Resetting LFSS IP Using VBAT
    2. 2.2 Power Domain Supply Detection
      1. 2.2.1 Start-Up Sequences
      2. 2.2.2 LFSS IP Behavior
    3. 2.3 LFXT, LFOSC
    4. 2.4 Independent Watchdog Timer (IWDT)
    5. 2.5 Tamper I/O
      1. 2.5.1 IOMUX Mode
      2. 2.5.2 Tamper Mode
        1. 2.5.2.1 Tamper Event Detection
        2. 2.5.2.2 Timestamp Event Output
        3. 2.5.2.3 Heatbeat Generator
    6. 2.6 Scatchpad Memory (SPM)
    7. 2.7 Real-Time Clock (RTC)
    8. 2.8 VBAT Charging Mode
  6. 3Application Examples
    1. 3.1 Tamper I/O Heartbeat Example
    2. 3.2 RTC Tamper I/O Timestamp Event Example
    3. 3.3 Supercapacitor Charging Example
    4. 3.4 LFOSC Transition Back to LFXT Example
    5. 3.5 RTC_A Calibration
      1. 3.5.1 Peripheral ADC 12
      2. 3.5.2 RTC_A

3.5 RTC_A Calibration

The accuracy of internal oscillators is within percentages while external crystals are in parts per million (ppm). At the expense of higher power consumption, crystal oscillators are highly accurate due to the precise cut, shape, and size. However, the frequency the oscillators resonate at is still subject to external factors. Temperature, aging, mechanical shock and vibration, and gravity all have an effect on the accuracy of the crystal. This example shows how to calibrate the RTC of LFSS when offset and temperature-based errors are measured.