STM32 GPIOS mode.

[Muzahir Hussain]

Posted on February 03, 2018 at 18:07

In STM32 there are two modes to configure GPIOS, input and output.

In input mode we have, 

• Analog mode
• Floating Input
• Input with pull-up/pull-down

In output mode,

• General purpose output push-pull
• General purpose output Open-drain
• Alternate function output push-pull
• Alternate function output Open-drain.

Can any one explain each of these configurations in detail?

Thanks!

#gpio #stm-32 #input #output

[Bogdan Golab]

Posted on February 03, 2018 at 19:24

Details:

http://www.st.com/content/ccc/resource/technical/document/reference_manual/59/b9/ba/7f/11/af/43/d5/CD00171190.pdf/files/CD00171190.pdf/jcr:content/translations/en.CD00171190.pdf

 

or in any Reference Guide for particular MCU

[Tesla DeLorean · Accepted solution]

Posted on February 04, 2018 at 01:02

These are pretty standard concepts, what's challenging your understanding here?

The 'Alternate Function' in ST's nomenclature is attached to the Peripheral's IO logic rather than a user driven GPIO

The 'Analogue Input' turns off the digital sections Schmitt Trigger input, reduces the noise

https://en.wikipedia.org/wiki/Schmitt_trigger

 

Push-Pull, a pair of transistors either drive the output high/low to the supply rails.

Open-Drain (like Open-Collector), a single transistor than can drive to ground, the high state is left floating, and can be pulled up internally or externally.