To measure the current draw of the MSPM0G5187 MCU using a multimeter, use the 3V3 jumper on the J101 jumper isolation block. The current measured includes the target device, LaunchPad™ circuits, and any current drawn through the BoosterPack™ plug-in module headers. To measure ultra-low power, follow these steps:
- Remove the 3V3 and VUSB jumper in the J101 isolation block, and attach an ammeter across the 3V3 jumper.
- Consider the effects that the VUSB channel (which supplies the power to the MSPM0 USB PHY), backchannel UART, and any circuitry attached to the MSPM0G5187 have on the current draw. Consider disconnecting the backchannel UART at the isolation jumper block, or at least consider the current sinking and sourcing capability in the final measurement. Connect the VUSB to 3V3 if USB interface is used with the MSPM0G5187.
- Remove the jumper in J6 to disconnect the on-board analog component, including the SD card, microphone, and audio ADC.
- Make sure there are no floating inputs or outputs (I/Os) on the MSPM0G5187. This causes unnecessary extra current draw. Every I/O is either driven or, if the I/O is an input, is pulled or driven to a high or low level.
- Begin target execution.
- For the most accurate current measurements, place the device in free run mode and disconnect programming signals between the MSPM0G5187 and the debug portion of the board (header J101).
- Measure the current. Remember that if the current levels are fluctuating, then getting a stable measurement can be difficult. Measuring the quiescent states is easier.