SLAA828B March   2018  – August 2021 MSP430FR2000 , MSP430FR2032 , MSP430FR2033 , MSP430FR2100 , MSP430FR2110 , MSP430FR2111 , MSP430FR2310 , MSP430FR2311 , MSP430FR2422 , MSP430FR2433 , MSP430FR2512 , MSP430FR2522 , MSP430FR2532 , MSP430FR2533 , MSP430FR2632 , MSP430FR2633 , MSP430FR4131 , MSP430FR4132 , MSP430FR4133

 

  1.   Trademarks
  2. 1Introduction
  3. 2ADC Low-Power Sampling Software Design
    1. 2.1 System Clock Source Selection
    2. 2.2 ADC Clock Source Selection
    3. 2.3 Initialization of Unused GPIO Pins
  4. 3ADC Error Correction and Experimental Testing
    1. 3.1 Error Correction
    2. 3.2 Accuracy Test
  5. 4Time-Division Multiplexing of the ADC to Achieve Additional Channel Acquisition
  6. 5Summary
  7. 6References
  8. 7Revision History

1 Low-Power Battery Voltage Measurement Using the On‑Chip VREF and 10‑Bit ADC of MSP430FR4xx and MSP430FR2xx MCUs

MSP430™ MCUs have low power consumption characteristics, making them widely used in battery-powered products. To ensure the stability of the system power supply, this application report describes how to detect the power supply voltage. A low-voltage alarm is performed when the voltage is lower than the set safe power supply threshold. The traditional method of battery voltage detection is usually through a power supply voltage divider and sampling through the ADC to achieve detection. The voltage divider detection solution needs extra external circuits, which increases the system cost, volume and power consumption.

Based on the MSP430 FRAM series of MCUs, for the application of battery direct power supply, a scheme of low-power supply voltage detection is proposed, using the on-chip 10-bit ADC without an external voltage divider circuit. The verification results of the scheme are given.

Keywords: Low-power sampling, battery-powered