GPIO concepts
Notes on GPIO concepts
Last updated
Notes on GPIO concepts
Last updated
MCUs have PORTS and PINS , PORTS are a collection of PINS and each PIN has a functionality thats assigned by the manufacturer
GPIO is used as switch , interrupts , in SPI as CS etc
GPIO - General Purpose Input Output has the below structure
PIN of an MCU can be configured as Input with pullup or pulldown resistors
Why pullup or pulldown ? Because if a PIN doesnt have a internal pullup or extenal pullup/down activated then it will be in floating state when nothing is connected and this will lead to wrong input read values
floating state can also cause leakage current (the mosfets will turn on partially and the current will leak)
Output PIN can be in open drain (pulled low when 0 but floating when 1) so it requires an external pullup resistor (use this when the current to be sourced needs to be higher than what mosfet / PIN can source)
Output PIN can be in Push pull configuration and this doesnt require a pullup resistor