Current measurement in STM32N6570-Discovery Kit

[Tirth]

Hello,

I am currently using STM32N6657XOHXQ(Discovery Kit), I am currently running UART_HyperTerminal_IT example given in CubeMX Example. I need to measure the current consumption by board for that. I have removed Resistor (R31)  as

For external SMPS Output power mode, and my assumption is that after removing resistor and placing current measurement device between 3 and 4 pin of CN2 connector the current should be measured and prints should start but when i remove Current measurement device from the loop, the prints should be stopped as the path will be open. Still i am getting the print on console. Can you please prove the detailed steps to measure current consumption of the MCU Core.

[RomainR.]

Hello @Tirth 

Refer to MB1939-N6570-C02 Board schematic in page 5. 

https://www.st.com/en/evaluation-tools/stm32n6570-dk.html#cad-resources:~:text=MB1939%2DN6570%2DC02%20Board%20schematic

In addition to desoldering R31, there is a series shunt resistor R35.

The VDDCore current measurement method on CN2 between pin 3 and 4, must be done through the 50mΩ R35 shunt resistor with a voltmeter measuring the voltage drop. The current can then be determined by Iddcore = VDDCore / R35. Do not use an ampere meter.
VDDCore depends on the configuration of the external DC-DC U2 (TPS62088YFP). Either 0.81V in VOS_NOMINAL or 0.89V in VOS_OVERDRIVE by the state of GPIO PF4. By default, PF4=Low, VDDCore is set to VOS_NOMINAL 0.81V and the STM32N6 CPU frequency is set to 600MHz.

Let me know if it helps?
Best regards,

Romain,