opensteno_qmk/docs/internals_gpio_control.md
James Young b272c035ba
[Docs] Random Fixes (#8340)
* fix CLI section links in the Summary

* fix heading in Pointing Device doc

* fix headings in PS/2 Mouse Support doc

* add explicit section ids to I2C Master Driver doc

* reformat GPIO Controls table

Much like the I2C Master Driver doc, I found this a bit less than ideal to read. (The table was actually wider than the space available for it.)

Reformatted so each GPIO function is an H3 heading, followed by a paragraph and a table of each architecture's old-style function.

* migrate changes from I2C Master Driver doc to Japanese translation

* add explicit anchors to I2C Master Driver docs

* fix code block language markers

The language markers are case-sensitive; using the wrong case means the syntax highlighting doesn't work.

Good: ```c
Bad: ```C

* restore Japanese I2C Master Driver doc to current master

Can't update the internal tracking references accurately until the changes to the English doc are committed to master.

* add explicit anchors to edited files

* change ChibiOS/ARM to ARM/ChibiOS

Because ARM/ATSAM is also a thing that exists.

* fix code block language markers again

Used the wrong markers in a few spots. Also these are apparently always supposed to be lowercase.

* add section anchors to cli.md

* restore table formatting on GPIO Control doc

* remove changes to _summary.md
2020-03-15 20:29:11 -07:00

2.5 KiB

GPIO Control :id=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 :id=functions

The following functions can provide basic control of GPIOs and are found in quantum/quantum.h.

Function Description Old AVR Examples Old ChibiOS/ARM Examples
setPinInput(pin) Set pin as input with high impedance (High-Z) DDRB &= ~(1<<2) palSetLineMode(pin, PAL_MODE_INPUT)
setPinInputHigh(pin) Set pin as input with builtin pull-up resistor DDRB &= ~(1<<2); PORTB |= (1<<2) palSetLineMode(pin, PAL_MODE_INPUT_PULLUP)
setPinInputLow(pin) Set pin as input with builtin pull-down resistor N/A (Not supported on AVR) palSetLineMode(pin, PAL_MODE_INPUT_PULLDOWN)
setPinOutput(pin) Set pin as output DDRB |= (1<<2) palSetLineMode(pin, PAL_MODE_OUTPUT_PUSHPULL)
writePinHigh(pin) Set pin level as high, assuming it is an output PORTB |= (1<<2) palSetLine(pin)
writePinLow(pin) Set pin level as low, assuming it is an output PORTB &= ~(1<<2) palClearLine(pin)
writePin(pin, level) Set pin level, assuming it is an output (level) ? PORTB |= (1<<2) : PORTB &= ~(1<<2) (level) ? palSetLine(pin) : palClearLine(pin)
readPin(pin) Returns the level of the pin _SFR_IO8(pin >> 4) & _BV(pin & 0xF) palReadLine(pin)

Advanced Settings :id=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 is used.