gpio.h File Reference

GPIO configuration and service functions. More...

#include <stdbool.h>
#include <stdint.h>
#include <avr/io.h>

Include dependency graph for gpio.h:

This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures
struct	gpio_pin
	Configuration of a single GPIO pin. More...
struct	gpio_mapping
	Maps a GPIO pin to its designated type / function. More...
struct	gpio_header
	Configurations of the GPIO pins contained in one 10-pin header. More...
struct	jumpers
	This struct represents the four solder jumpers on the bottom side of the PCB. More...
struct	gpio
	Configurations for all available GPIO pins. More...

Enumerations
enum	gpio_input_event { GPIO_INPUT_EVENT_NONE, GPIO_INPUT_EVENT_SHORT, GPIO_INPUT_EVENT_LONG }
	Possible GPIO input events. More...
enum	gpio_type {   GPIO_INPUT, GPIO_INPUT_PULLDOWN, GPIO_INPUT_PULLUP, GPIO_OUTPUT,   GPIO_UNUSED }
	Function / type of a GPIO pin. More...

Functions
void	configure_gpio_pin (const struct gpio_pin *pin, enum gpio_type type)
	Configures a GPIO pin. More...
void	init_gpio_module (const struct gpio_mapping mappings[], uint8_t mappings_size)
	Initializes the GPIO module. More...
bool	poll_gpio_input (const struct gpio_pin pin, enum gpio_type type)
	Polls a GPIO input pin. More...
enum gpio_input_event	poll_gpio_input_timeout (const struct gpio_pin pin, enum gpio_type type, uint8_t timeout)
	Polls a GPIO input pin with timeout. More...
static void	gpio_drive_high (const struct gpio_pin pin)
	Enables a GPIO output pin. More...
static void	gpio_drive_low (const struct gpio_pin pin)
	Disables a GPIO output pin. More...
static bool	gpio_get (const struct gpio_pin pin)
	Reads the state of a GPIO input pin. More...
static void	gpio_set (const struct gpio_pin pin, bool value)
	Sets a GPIO output pin to the specified state. More...
static void	gpio_toggle (const struct gpio_pin pin)
	Toggles a GPIO output pin. More...

Variables
const struct gpio	gpio
	A global structure with all available GPIO pins. More...

Detailed Description

GPIO configuration and service functions.

Enumeration Type Documentation

gpio_input_event

enum gpio_input_event

Possible GPIO input events.

See also

poll_gpio_input_timeout

Enumerator
GPIO_INPUT_EVENT_NONE	Nothing happened :-(.
GPIO_INPUT_EVENT_SHORT	A GPIO input pin was seen logical "high" briefly.
GPIO_INPUT_EVENT_LONG	A GPIO input pin was seen logical "high" for some time.

gpio_type

enum gpio_type

Function / type of a GPIO pin.

Enumerator
GPIO_INPUT	The GPIO pin acts as an input.
GPIO_INPUT_PULLDOWN	The GPIO pin acts as an input and is pulled down.
GPIO_INPUT_PULLUP	The GPIO pin acts as an input and is pulled up.
GPIO_OUTPUT	The GPIO pin acts as an output.
GPIO_UNUSED	The GPIO pin is not used Unused pins are configured as inputs with pull-down

Function Documentation

configure_gpio_pin()

void configure_gpio_pin	(	const struct gpio_pin *	pin,
		enum gpio_type	type
	)

Configures a GPIO pin.

Parameters

pin	the GPIO pin to configure
type	the desired function / type of the pin

gpio_drive_high()

static void gpio_drive_high ( const struct gpio_pin  pin )

inlinestatic

Enables a GPIO output pin.

Parameters

pin	the GPIO pin

gpio_drive_low()

static void gpio_drive_low ( const struct gpio_pin  pin )

inlinestatic

Disables a GPIO output pin.

Parameters

pin	the GPIO pin

gpio_get()

static bool gpio_get ( const struct gpio_pin  pin )

inlinestatic

Reads the state of a GPIO input pin.

Parameters

pin	the GPIO pin

Returns

true if the input pin is driven high; false otherwise

gpio_set()

static void gpio_set ( const struct gpio_pin  pin, bool  value  )

inlinestatic

Sets a GPIO output pin to the specified state.

Parameters

pin	the GPIO pin
value	true enables the output; false disables it

gpio_toggle()

static void gpio_toggle ( const struct gpio_pin  pin )

inlinestatic

Toggles a GPIO output pin.

Parameters

pin

init_gpio_module()

void init_gpio_module	(	const struct gpio_mapping	mappings[],
		uint8_t	mappings_size
	)

Initializes the GPIO module.

Configures all available GPIO pins to a standard configuration. If an array of pin type mappings was supplied, those are also applied.

Parameters

mappings	an array of pin type mappings or NULL
mappings_size	number of elements in the type mappings array or 0

poll_gpio_input()

bool poll_gpio_input	(	const struct gpio_pin	pin,
		enum gpio_type	type
	)

Polls a GPIO input pin.

Automatically de-bounces the pin if it is detected as active and returns as soon as the input returns to logical 0. Warning: Uses busy waiting!

Parameters

pin	the GPIO input pin to poll
type	the GPIO input type (pull-up or pull-down)

Returns

true if the input pin reads logical 1

See also

poll_gpio_input_timeout

poll_gpio_input_timeout()

enum gpio_input_event poll_gpio_input_timeout	(	const struct gpio_pin	pin,
		enum gpio_type	type,
		uint8_t	timeout
	)

Polls a GPIO input pin with timeout.

Reads and de-bounces an input pin and measures how long it is in logical high-state continuously. After a given amount of time the function announces the event by returning GPIO_INPUT_EVENT_LONG. If the input pin returns to low before the timeout was reached, GPIO_INPUT_EVENT_SHORT is returned. This function uses busy waiting, so all background tasks are stalled until the timeout is reached. When the timeout is set to zero, this function blocks until the input pin reads logical low again, which is what poll_gpio_input does.

Parameters

pin	the GPIO input pin to poll
type	the GPIO input type (pull-up or pull-down)
timeout	the timeout in [s/10], or 0 for infinity

Returns

the detected input event or GPIO_INPUT_EVENT_NONE

Variable Documentation

gpio

const struct gpio gpio

A global structure with all available GPIO pins.

This data structure provides a nice way to address GPIO pins. The pins are grouped into three headers with eight pins each and a group for the four solder jumpers - exactly representing the hardware interface. You can use these aliases to configure the pins you need and to get / set the state of the pin.

See also

configure_gpio_pin

init_gpio_module

gpio_get

gpio_set