gistfile1.txt

static void initialize(FAR const struct sonar_lowerhalf_s* lower)
{
  /* set pins as GPIOs */
  lpc43_pin_config(PINCONF_PINS6 | PINCONF_PIN_1 | PINCONF_PULLDOWN | PINCONF_FUNC0); // GPIO0 (GPIO3[0]) -> trigger
  lpc43_pin_config(PINCONF_PINS6 | PINCONF_PIN_5 | PINCONF_PULLDOWN | PINCONF_FUNC0); // GPIO2 (GPIO3[4]) -> echo

  /* setup GPIOs */
  lpc43_gpio_config(GPIO_PORT3 | GPIO_PIN0 | GPIO_MODE_OUTPUT); // GPIO0
  lpc43_gpio_config(GPIO_PORT3 | GPIO_PIN4 | GPIO_MODE_PININTR | GPIO_INT_EDGE_BOTH | GPIO_PININT0); // GPIO2

  /* set trigger to low */
  lpc43_gpio_write(GPIO_PORT3 | GPIO_PIN0, false);
}

static void trigger(FAR const struct sonar_lowerhalf_s* lower)
{
  /* send a 10uS pulse, as per datasheet */
  lpc43_gpio_write(GPIO_PORT3 | GPIO_PIN0, true);
  up_udelay(15);
  lpc43_gpio_write(GPIO_PORT3 | GPIO_PIN0, false);
}

static void enable(FAR const struct sonar_lowerhalf_s* lower, sonar_interrupt_t handler, FAR void* arg)
{
  if (handler)
  {
    printf("enabling IRQ\n");
    interrupt_handler = handler;
    interrupt_argument = arg;

    int ret = irq_attach(LPC43M4_IRQ_PININT0, (xcpt_t)sonar_interrupt);
    if (ret == OK) printf("OK\n");
    up_enable_irq(LPC43M4_IRQ_PININT0);
    /* TODO: enable pin interrupt here? maybe an IRQ is triggered here due to previous events */
  }
  else {
    printf("disabling IRQ\n");
    up_disable_irq(LPC43M4_IRQ_PININT0);
    interrupt_handler = NULL;
  }
}

static int sonar_interrupt(int irq, FAR void *context)
{
  if (interrupt_handler)
    interrupt_handler(&g_sonarlower, interrupt_argument);

  return OK;
}