4.6.4 Low-Power Measurement

Power to the PIC32CM3204GV00064 microcontroller comes from the on-board power supply and the VTG pin through a 100-mil pin-header marked with POWER in silkscreen (J101). To measure the power consumption of the PIC32CM3204GV00064 microcontroller and other peripherals connected to the board, cut the Target Power strap (J101) on the bottom side and connect an ammeter across it.

Tip: A 100-mil pin-header can be soldered into the Target Power strap (J101) footprint for a simple connection of an ammeter. Place a jumper cap on the pin-header once the ammeter is no longer needed.

To measure the lowest possible power consumption, follow these steps:

  1. Cut the POWER strap with a sharp tool.
  2. Solder a 1x2 100 mil pin-header in the footprint.
  3. Connect an ammeter to the pin header.
  4. Write firmware that:
    1. Tri-states any I/O connected to the on-board debugger.
    2. Sets the microcontroller in its Low-Power Sleep mode.
  5. Program the firmware into the PIC32CM3204GV00064 microcontroller.
Info: The on-board level shifters will draw a small amount of current even when unused. Each level shifter has a maximum of 2 μA leakage current. Therefore, the worst-case maximum current draw for the five on-board level shifters is 10 μA. Prevent leakage current through an I/O pin connected to a level shifter by keeping the I/O pin tri-stated. All I/Os connected to the on-board debugger are listed in On-Board Debugger Connections section. The on-board level shifters can be completely disconnected, preventing leakage, as described in Disconnecting the On-Board Debugger section.