opensteno_qmk/docs/internals_gpio_control.md
noroadsleft 3c26f07f5a Grammatical fixes for GPIO Control doc (#4869)
* Grammatical fixes for GPIO Control doc

I found the Advanced Settings section to be poorly written.

* Commit suggestions from fauxpark

* Change first instance of "microcontroller" to match suggestion
2019-01-17 22:13:09 -08:00

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# GPIO Control
QMK has a GPIO control abstraction layer which is microcontroller agnostic. This is done to allow easy access to pin control across different platforms.
## Functions
The following functions can provide basic control of GPIOs and are found in `quantum/quantum.h`.
|Function |Description |
|----------------------|------------------------------------------------------------------|
|`setPinInput(pin)` |Set pin as input with high impedance (High-Z) |
|`setPinInputHigh(pin)`|Set pin as input with build in pull-up |
|`setPinInputLow(pin)` |Set pin as input with build in pull-down (Supported only on STM32)|
|`setPinOutput(pin)` |Set pin as output |
|`writePinHigh(pin)` |Set pin level as high, assuming it is an output |
|`writePinLow(pin)` |Set pin level as low, assuming it is an output |
|`writePin(pin, level)`|Set pin level, assuming it is an output |
|`readPin(pin)` |Returns the level of the pin |
## Advanced Settings
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.