To measure the current draw of the
MSP430FR2355 MCU using a multimeter, use the 3V3 jumper on the
J101 jumper isolation block. The
current measured includes the target device and any current drawn through the
BoosterPack plug-in module headers.
To measure ultra-low power, follow
these steps:
- Remove the 3V3 jumper in the J101
isolation block, and attach an ammeter across this jumper.
- Consider the effect that the
backchannel UART and any circuitry attached to the MSPM0G3507 can have on the
current draw. Consider disconnecting these at the isolation jumper block, or at
least consider the current sinking and sourcing capability in the final
measurement.
- Disconnect unnecessary
jumpers as outlined in the jumper map of Table 2-1. In particular, Analog Power jumper J13 must be removed if not using
the thermistor or OPA2365 circuits.
- Make sure there are no floating
inputs or outputs on the MSPM0G3507. This causes unnecessary extra current draw.
Every I/O is either driven out or, if there is an input, then the I/O is pulled
or driven to a high or low level.
- Begin target execution.
- Measure the current. Keep in mind
that if the current levels are fluctuating, then getting a stable measurement is
difficult. Measuring quiescent states is easier.
EnergyTrace technology can also be
used to compare various current profiles and better optimize your energy
performance.