STM32F411 Discovery can not power the external led using 3V pin.

TThin.1 · ‎2022-03-09

Hello everyone. I have a stm32f411 discovery board. Long time ago it worked fine. But now when I connect the external led with GND and 3V pin, the led is not on (the led is ok, I already test it with an arduino board). I don’t know why. Other functions on the board are working fine. 4 PD leds and the user button are working fine. I measure the voltage output in each pin using ADC of the arduino board and the voltage is also fine. It’s 4.5V ~ 4.6V on 5V pin, 3V ~ 3,3V on 3V and other GPIO pins with output high, 0V ~ 0.2V on GND pin and other GPIO pins with output low. I just want to test the I2C function but I can not because of this problem. The other device can not be powered or receive data from this board.

Peter BENSCH · ‎2022-03-10

Welcome, @TThin.1, to the community!

Unfortunately, you did not draw how you connected the important things.

If I understand correctly, you can successfully measure the 3V at the 3V output?

If you then connect an external LED (hopefully with a series resistor) to 3V and GND, it does not light up?

Regards

/Peter

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