GPIO connection on MCU

[balogandrej9184]

Hello,

I'm relatively new to PCB designing and I've already learned a lot of things, but I'm still not sure about connecting 2 components through GPIO pins. I have IIS2MDC magnetometer and I would like to connect INT/DRDY pin to STM32H747AI. Let's say I choose PG0 as my GPIO pin. Is all I have to do just connect it to PG0 with some resistor for current limitation and I'm done? (I know I need to also check voltage leves of both pins but I'm really getting lost in this) Or when do I need to use pull-up/pull-down resistor?

These are all unused GPIO signals in my project:

Thank you very much in advance for any recommendation.

Best regards

[TDK]

Pretty much, just connect the pins.

For DRDY, it likely has an internal pulldown on the IIS2MDC side, so an external one is not needed. If it does not, you could also use the STM32's internall pullup/pulldown to put it at a defined state.

You need an external pullup/pulldown when:

• You need the signal to have a known value (high or low) when the chip is in reset.
• The internal pullup/pulldown is not strong enough (e.g. in the case of I2C, pullup should be 4.7 kOhm, or so)

A resistor to limit the current isn't generally needed, but you can add it if you want. If you program it correctly, the pin will never be driven by the STM32.