2.2.5.2 Power Modes

The Demo Meter application operates in the following modes:

• Normal or measurement operating mode: The meter firmware enters in normal mode after the Metrology DSP is started and running. This mode supports the meter application taking measurements, LCD management, communication with the user through the command terminal, and anti-tampering features demonstration (tamper detection, with timestamp registering and automatic erasing of GPBR registers).
• Battery: The Demo Meter application enters a Low-Power mode (Back-Up mode) in two ways:
  • When the user enters the command DCB in the console.
  • When the Scroll-up button is pressed, and then without releasing it the Scroll-down button is pressed.

  The system wakes up when the user presses the TAMPER or FWUP buttons if the main power supply was restored.

  Note: The user can easily change the code to add other transition modes to Low-Power mode. In some cases, it could be useful to switch to Low-Power mode when a power outage is detected or depending on the micro controller voltage supply monitor information. These transitions may be combined with writing on external memory to store relevant data.

At power-up, the Demo Meter application initializes the PIC32CXMTx-DB demo board and restores the metrology registers according to the information stored in non-volatile memory, or to the default values, if no information was stored in memory. Energy records are restored. After that, it transitions to Normal mode.