GPIO

GPIO library functions. More...

Functions
int	gpio_init (unsigned int pin, unsigned int dir)
	Initialize the GPIO interface for the pin numbered pin on the Raspberry Pi P1 header in the direction specified by dir. dir should be either "in" or "out", for which the defined constants INPUT, IN, OUTPUT or OUT may be used.
int	gpio_set_int (unsigned int pin, void(*isr)(int), char *mode)
	Set isr as the interrupt service routine (ISR) for pin numbered pin on the Raspberry Pi P1 header. mode should be one of the strings "rising", "falling" or "both" to indicate which edge(s) the ISR is to be triggered on. The function isr is called whenever the edge specified occurs, receiving as argument the number of the pin which triggered the interrupt.
int	gpio_clear_int (unsigned int pin)
	Clears any interrupt service routine (ISR) set on the pin numbered pin on the Raspberry Pi P1 header. The ISR will have been set originally by a call to gpio_set_int.
int	gpio_write (unsigned int pin, unsigned int val)
	Set the pin numbered pin on the Raspberry Pi P1 header to the value specified by val. dir should be either "0" or "1". The defined constants LOW or OFF may be used instead of 0 and HIGH or ON instead of 1/.
int	gpio_read (unsigned int pin)
	Read the value on the pin numbered pin on the Raspberry Pi P1 header.
int	gpio_release (unsigned int pin)
	The inverse of gpio_init. Frees the pin numbered pin on the Raspberry Pi P1 header, so it can be used for other purposes.

Detailed Description

GPIO library functions.

Function Documentation

int gpio_clear_int

(

unsigned int

pin

)

Clears any interrupt service routine (ISR) set on the pin numbered pin on the Raspberry Pi P1 header. The ISR will have been set originally by a call to gpio_set_int.

Parameters

Pin	number which has an interrupt attached

Returns

Returns 1 on success. Never fails

Definition at line 304 of file pi_gpio.c.

int gpio_init	(	unsigned int	pin,
		unsigned int	dir
	)

Initialize the GPIO interface for the pin numbered pin on the Raspberry Pi P1 header in the direction specified by dir. dir should be either "in" or "out", for which the defined constants INPUT, IN, OUTPUT or OUT may be used.

Parameters

pin	Pin number
dir	Direction of pin (input or output)

Returns

1 for success, -1 for failure

Definition at line 125 of file pi_gpio.c.

int gpio_read

(

unsigned int

pin

)

Read the value on the pin numbered pin on the Raspberry Pi P1 header.

Parameters

pin	Pin number to read from

Returns

On success, returns 0 or 1 depending on whether the pin is low or high respectively. On failure returns -1.

Definition at line 366 of file pi_gpio.c.

int gpio_release

(

unsigned int

pin

)

The inverse of gpio_init. Frees the pin numbered pin on the Raspberry Pi P1 header, so it can be used for other purposes.

Parameters

pin	Pin number to release

Returns

1 for success, -1 for failure

Definition at line 398 of file pi_gpio.c.

int gpio_set_int	(	unsigned int	pin,
		void(*)(int)	isr,
		char *	mode
	)

Set isr as the interrupt service routine (ISR) for pin numbered pin on the Raspberry Pi P1 header. mode should be one of the strings "rising", "falling" or "both" to indicate which edge(s) the ISR is to be triggered on. The function isr is called whenever the edge specified occurs, receiving as argument the number of the pin which triggered the interrupt.

Parameters

pin	Pin number to attach interrupt to
isr	Interrupt service routine to call
mode	Interrupt mode

Returns

Returns 1 on success. Never fails

Definition at line 275 of file pi_gpio.c.

int gpio_write	(	unsigned int	pin,
		unsigned int	val
	)

Set the pin numbered pin on the Raspberry Pi P1 header to the value specified by val. dir should be either "0" or "1". The defined constants LOW or OFF may be used instead of 0 and HIGH or ON instead of 1/.

Parameters

pin	Pin number to write to
val	Value to set (0 or 1)

Returns

1 for success, -1 for failure

Definition at line 322 of file pi_gpio.c.