GPIO outputs are in high-impedance state

Question

I have two of the STM32H747I-DISCO boards. I have used STM32CubeIDE to create a simple project for the boards. I followed AN5361 and am able to debug and see the CM7 and CM4 cores running.

I've added code to toggle the board LEDs (port I) but don't see any activity - even with an oscilloscope. The IDE did create the code to enable the GPIO clock (__HAL_RCC_GPIOI_CLK_ENABLE() ).

I didn't have any trouble getting blinking LEDs on my STM32F407G-DISC1 boards.

The issue seems to be that the four GPIO pins for the LEDs are in a high-impedance state even though Pinout View shows that they're all configured as outputs. The pins are floating at between 1V and 2V (with the scope probe weakly pulling to GND). I can alter the voltage on the pins by connecting a 100k resistor from a pin to either 3.3V or GND, so they're definitely floating.

I suspect that there is a clocking issue to GPIO Port I, but I'm new to the STM world and don't know where to start.

Can someone please point me in the right direction?

AScha.3 · Accepted Answer

did you assign the core, thats setting the port, in Cube to this port ? (iirr the blue area F4 and F7 )

Tinnagit · Answer

For GPIOs that configuration as Output that it has many type of configuration such as Push-Pull or open-drain
and you should set initial state of them too.

But it's never go to 0 volt on every stage because it's drive by High-side and Low-side transistor which they has voltage on Vce and it's about 1 voltage.

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