3. BGPR Retention

3.1. Overview

This example project demonstrates the data retention function of the BGPR register.

3.2. Board Setting

Ensure that the VBAT pin is powered, for example, greater than 3V.

HPM6800EVK has a known issue about VBAT, please refer to Board known issue details

3.3. Running the example

• When the Retention field of BPOR is initialized and set, the serial terminal will output the following information and the LED will not light up.

  bgpr retention example
  bgpr retention enable and data initialized, please keep vbat and power down!
  

  Or

  bgpr retention example
  bgpr data retention failure, index: 0!
  bgpr data retention failure, index: 1!
  bgpr data retention failure, index: 2!
  bgpr data retention failure, index: 3!
  bgpr data retention failure, index: 4!
  bgpr data retention failure, index: 5!
  bgpr data retention failure, index: 6!
  bgpr data retention failure, index: 7!
  Because bgpr data compare failure, so re-initialize bgpr data, please keep vbat and power down again!
  

• After power off/on again or press reset. The serial port terminal will output the data retention function verification result. For example, when the verification is successful, the output log is as follows:

  bgpr retention example
  bgpr data retention success!
  

• In addition, the status of the LED light can also indicate the verification result of the data retention function. If the verification is successful, the LED will light up; Otherwise, it will not light up.