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    The example msp430fr5994x_lpm4-5_02.c is supposed to show how little current is used in this mode. In the file it says: // MSP430FR5x9x Demo - Entering and waking up from LPM4.5 via P1.3 interrupt // with SVS disabled // // Description: Download and run the program. When entered LPM4.5, no LEDs // should be on. Use a multimeter to measure current on JP1 and // compare to the datasheet. When a positive voltage is applied // to P1.3 the device should wake up from LPM4.5. This will enable // the LFXT oscillator and blink the LED (on P1.0). Even for a high-end multimeter this current is too low to be accurately measured. So I helped myself this way: - power the processor from the supercap - a 10k resistor with two antiparallel diodes act as a shunt, - connect the volt meter across the supercap, not across the processor 0.43mV over a 10k resistor gives 43 Nanoamps. (!) Yes, the datasheet (page 32) is right, typical value at 25°C is 45nA. A CR2032 (200mAh) cell would allow the processor to wait for an interrupt for 530 years.