Add GPIO config, interrupt registers, GPIO interrupt support, 'button' example

examples/button/button.c

@@ -0,0 +1,84 @@
+/* Respond to a button press.
+ *
+ * This code combines two ways of checking for a button press -
+ * busy polling (the bad way) and button interrupt (the good way).
+ *
+ * This sample code is in the public domain.
+ */
+#include "espressif/esp_common.h"
+#include "espressif/sdk_private.h"
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+#include "esp8266.h"
+
+/* pin config */
+const int gpio = 0;   /* gpio 0 usually has "PROGRAM" button attached */
+const int active = 0; /* active == 0 for active low */
+const gpio_interrupt_t int_type = INT_FALLING;
+#define GPIO_HANDLER gpio00_interrupt_handler
+
+
+/* This task polls for the button and prints the tick
+   count when it's seen.
+
+   Debounced to 200ms with a simple vTaskDelay.
+
+   This is not a good example of how to wait for button input!
+*/
+void buttonPollTask(void *pvParameters)
+{
+    printf("Polling for button press on gpio %d...\r\n", gpio);
+    while(1) {
+	while(gpio_read(gpio) != active)
+	{
+	    taskYIELD();
+	}
+	printf("Polled for button press at %dms\r\n", xTaskGetTickCount()*portTICK_RATE_MS);
+	vTaskDelay(200 / portTICK_RATE_MS);
+    }
+}
+
+/* This task configures the GPIO interrupt and uses it to tell
+   when the button is pressed.
+
+   The interrupt handler communicates the exact button press time to
+   the task via a queue.
+
+   This is a better example of how to wait for button input!
+*/
+void buttonIntTask(void *pvParameters)
+{
+    printf("Waiting for button press interrupt on gpio %d...\r\n", gpio);
+    xQueueHandle *tsqueue = (xQueueHandle *)pvParameters;
+    gpio_set_interrupt(gpio, int_type);
+
+    uint32_t last = 0;
+    while(1) {
+	uint32_t button_ts;
+	xQueueReceive(*tsqueue, &button_ts, portMAX_DELAY);
+	button_ts *= portTICK_RATE_MS;
+	if(last < button_ts-200) {
+	    printf("Button interrupt fired at %dms\r\n", button_ts);
+	    last = button_ts;
+	}
+    }
+}
+
+static xQueueHandle tsqueue;
+
+void GPIO_HANDLER(void)
+{
+    uint32_t now = xTaskGetTickCountFromISR();
+    xQueueSendToBackFromISR(tsqueue, &now, NULL);
+}
+
+void user_init(void)
+{
+    sdk_uart_div_modify(0, UART_CLK_FREQ / 115200);
+    gpio_enable(gpio, GPIO_INPUT);
+
+    tsqueue = xQueueCreate(2, sizeof(uint32_t));
+    xTaskCreate(buttonIntTask, (signed char *)"buttonIntTask", 256, &tsqueue, 2, NULL);
+    xTaskCreate(buttonPollTask, (signed char*)"buttonPollTask", 256, NULL, 1, NULL);
+}