GPIO library

Typedefs
typedef uint8_t	gpio_t

Enumerations
enum	gpio_direction_t { GPIO_DIR_INPUT = 0 , GPIO_DIR_OUTPUT = 1 }
enum	gpio_level_t { GPIO_LEVEL_LOW = 0 , GPIO_LEVEL_HIGH = 1 }

Functions
void	gpio_init (void)
void	gpio_destroy (void)
void	gpio_reset_pin (const gpio_t pin)
void	gpio_set_direction (const gpio_t pin, const gpio_direction_t direction)
gpio_direction_t	gpio_get_direction (const gpio_t pin)
void	gpio_set_level (const gpio_t pin, const gpio_level_t level)
gpio_level_t	gpio_get_level (const gpio_t pin)
void	gpio_reset (void)

Detailed Description

Functions for General Purpose I/O (GPIO) access to leds, buttons, etc.

All functions use a GPIO number from 0..NUM_PINS_SWITCHBOX-1.

The LED and button libraries are built on top of this library, but do not expose the full functionality of this library. Use this library when that is required. Also see the I/O switchbox (switchbox.h) and pin mapping (pinmap.h).

In particular, be aware that the numbering used in the high-level libraries is different from the underlying GPIO numbering.

• The button library uses 0..3 or BUTTON0..BUTTON3, and 0..1 or SWITCH0..SWITCH1, whereas GPIO uses SWB_BTN0..SWB_BTN3 and SWB_SW0..SWB_SW1.
• The LED library uses 0..3 or LED0..LED1 for green LEDs whereas GPIO uses SWB_LD0..SWB_LD3. It uses 0..1 or COLOR_LED0..COLOR_LED1 and the three color components (RGB) whereas GPIO uses SWB_LD4/5R/G/B.
• The PWM library uses 0..5 or PWM0..PWM5, whereas GPIO uses SWB_PWM0..SWB_PWM5.
• The UART library uses 0..1 or UART0..UART1, whereas GPIO uses SWB_UART0..SWB_UART1.
• The ADC library is slightly different. It uses ADC0..ADC5 (these are non-consecutive numbers), whereas GPIO uses SWB_A0..SWB_A5 (which are consecutive).

An example of using this library to turn LED0 on:

#include <libpynq.h>
int main (void)
{
  // initialize the Library
  gpio_init();
  // set LED 0 as output
  gpio_set_direction(SWB_LD0, GPIO_DIR_OUTPUT);
  // turn LED 0 on
  gpio_set_level(SWB_LD0, GPIO_LEVEL_HIGH);
  sleep_msec(1000);
  // cleanup after use
  leds_destroy(); // turn LEDs off
  pynq_destroy();
  return EXIT_SUCCESS;
}

Typedef Documentation

gpio_t

typedef uint8_t gpio_t

All functions use a GPIO numbered from 0..NUM_PINS_SWITCHBOX-1.

Definition at line 99 of file gpio.h.

Enumeration Type Documentation

gpio_direction_t

enum gpio_direction_t

Enumerate the direction state (input/output) of the pin

Enumerator
GPIO_DIR_INPUT	The GPIO pin is an input.
GPIO_DIR_OUTPUT	The GPIO pin is an output.

Definition at line 79 of file gpio.h.

gpio_level_t

enum gpio_level_t

Enumerate the signal level.

Enumerator
GPIO_LEVEL_LOW	A low signal
GPIO_LEVEL_HIGH	A high signal

Definition at line 89 of file gpio.h.

Function Documentation

gpio_destroy()

void gpio_destroy

(

void

)

De-initialize the GPIO library. This releases the memory map and memory allocated by gpio_init.

Definition at line 3 of file gpio.c.

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gpio_get_direction()

gpio_direction_t gpio_get_direction

(

const gpio_t

pin

)

Returns the direction the set pin is initialized in.

Parameters

pin	The GPIO pin to read the direction set in the shared memory system on the ARM processor.

Warning

Fails with program exit when pin is outside valid range.

Definition at line 6 of file gpio.c.

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gpio_get_level()

gpio_level_t gpio_get_level

(

const gpio_t

pin

)

Return the level of the GPIO pin.

Parameters

pin	The GPIO pin to read it state.

Returns

the output level of pin using enum gpio_level_t.

Warning

Fails with program exit when pin is outside valid range.

Definition at line 8 of file gpio.c.

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gpio_init()

void gpio_init

(

void

)

Initializes the GPIO library.

Definition at line 2 of file gpio.c.

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gpio_reset()

void gpio_reset

(

void

)

Reset all GPIO pins.

Definition at line 18 of file gpio.c.

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gpio_reset_pin()

void gpio_reset_pin

(

const gpio_t

pin

)

Function is currently a no-op placeholder for arduino compatibility.

Parameters

pin	The GPIO pin to reset.

Warning

Fails with program exit when LEDs were not initialized with the correct mode.

Definition at line 4 of file gpio.c.

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gpio_set_direction()

void gpio_set_direction	(	const gpio_t	pin,
		const gpio_direction_t	direction
	)

Set the GPIO pin as in input or output.

Parameters

pin	The GPIO pin to modify direction for.
direction	The direction to set on the pin.

Warning

Fails with program exit when pin or direction is outside valid range.

Definition at line 5 of file gpio.c.

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gpio_set_level()

void gpio_set_level	(	const gpio_t	pin,
		const gpio_level_t	level
	)

Set the level of the output GPIO pin. If the pin is configured as input, this function does nothing.

Parameters

pin	The GPIO pin to modify direction for
level	The level to set on the pin.

Warning

Fails with program exit when pin is outside valid range.

Definition at line 7 of file gpio.c.

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