docs/internals_gpio_control.md

   1 # GPIO Control
   2
   3 QMK has a GPIO control abstraction layer which is microcontroller agnostic. This is done to allow easy access to pin control across different platforms.
   4
   5 ## Functions
   6
   7 The following functions can provide basic control of GPIOs and are found in `quantum/quantum.h`.
   8
   9 |Function              |Description                                                       |
  10 |----------------------|------------------------------------------------------------------|
  11 |`setPinInput(pin)`    |Set pin as input with high impedance (High-Z)                     |
  12 |`setPinInputHigh(pin)`|Set pin as input with build in pull-up                            |
  13 |`setPinInputLow(pin)` |Set pin as input with build in pull-down (Supported only on STM32)|
  14 |`setPinOutput(pin)`   |Set pin as output                                                 |
  15 |`writePinHigh(pin)`   |Set pin level as high, assuming it is an output                   |
  16 |`writePinLow(pin)`    |Set pin level as low, assuming it is an output                    |
  17 |`writePin(pin, level)`|Set pin level, assuming it is an output                           |
  18 |`readPin(pin)`        |Returns the level of the pin                                      |
  19
  20 ## Advanced Settings
  21
  22 Each microcontroller can have multiple advanced settings regarding its GPIO. This abstraction layer does not limit the use of architecture-specific functions. Advanced users should consult the datasheet of their desired device and include any needed libraries. For AVR, the standard avr/io.h library is used; for STM32, the ChibiOS [PAL library](http://chibios.sourceforge.net/docs3/hal/group___p_a_l.html) is used.
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