Programming Example

The following example shows how to use the GPIO API to initialize the GPIO, enable interrupts, read data from pins, and write data to pins.

Example: Configure pins for use as input, interrupt, and output GPIOs.

int32_t i32Val;

//
// Enable the GPIOA peripheral
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

//
// Wait for the GPIOA module to be ready.
//
while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOA))
{
}

//
// Register the port-level interrupt handler.  This handler is the first
// level interrupt handler for all the pin interrupts.
//
GPIOIntRegister(GPIO_PORTA_BASE, PortAIntHandler);

//
// Initialize the GPIO pin configuration.
//
// Set pins 2, 4, and 5 as input, SW controlled.
//
GPIOPinTypeGPIOInput(GPIO_PORTA_BASE,
                     GPIO_PIN_2 | GPIO_PIN_4 | GPIO_PIN_5);

//
// Set pins 0 and 3 as output, SW controlled.
//
GPIOPinTypeGPIOOutput(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_3);

//
// Make pins 2 and 4 rising edge triggered interrupts.
//
GPIOIntTypeSet(GPIO_PORTA_BASE, GPIO_PIN_2 | GPIO_PIN_4, GPIO_RISING_EDGE);

//
// Make pin 5 high level triggered interrupts.
//
GPIOIntTypeSet(GPIO_PORTA_BASE, GPIO_PIN_5, GPIO_HIGH_LEVEL);

//
// Read some pins.
//
i32Val = GPIOPinRead(GPIO_PORTA_BASE,
                     (GPIO_PIN_0 | GPIO_PIN_2 | GPIO_PIN_3 |
                      GPIO_PIN_4 | GPIO_PIN_5));

//
// Write some pins.  Even though pins 2, 4, and 5 are specified, those pins
// are unaffected by this write because they are configured as inputs.  At
// the end of this write, pin 0 is low, and pin 3 is high.
//
GPIOPinWrite(GPIO_PORTA_BASE,
             (GPIO_PIN_0 | GPIO_PIN_2 | GPIO_PIN_3 |
              GPIO_PIN_4 | GPIO_PIN_5),
             (GPIO_PIN_3 | GPIO_PIN_4 | GPIO_PIN_5 | GPIO_PIN_6 |
              GPIO_PIN_7));

//
// Enable the pin interrupts.
//
GPIOIntEnable(GPIO_PORTA_BASE, GPIO_PIN_2 | GPIO_PIN_4 | GPIO_PIN_5);

Example: Configure Port B Pins for use as a UART 1.

//
// Enable the GPIOB peripheral
//
SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);

//
// Wait for the GPIOB module to be ready.
//
while(!SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOB))
{
}

//
// Configure GPIO Port B pins 0 and 1 to be used as UART1.
//
GPIOPinTypeUART(GPIO_PORTB_BASE, GPIO_PIN_0 | GPIO_PIN_1);

//
// Enable UART1 functionality on GPIO Port B pins 0 and 1.
//
GPIOPinConfigure(GPIO_PB0_U1RX);
GPIOPinConfigure(GPIO_PB1_U1TX);