samples: camera: Add hardware reset command

There is a possibility that the module would hang. Just to be sure,
issue a harware reset before taking a snapshot.

Signed-off-by: Ioannis Konstantelias <[email protected]>

Author: gon1332

samples/camera/README.rst

@@ -16,7 +16,8 @@ Requirements
 ************
 
 The demo assumes that a uCAM-III is connected to the UART_2 TX/RX of a Nucleo
-L496ZG. Also, the camera module should be powered by the 5V pin.
+L496ZG. The RST pin is connected to the PA3 pin of Nucleo. Also, the camera
+module should be powered by the 5V pin.
 
 Building and Running
 ********************

samples/camera/src/main.c

@@ -44,6 +44,9 @@ static int camera_take_snapshot(u8_t *data, u32_t *size)
 {
 	int ret;
 
+	/* Hardware reset the camera before every shot */
+	ucam3_reset();
+
 	/* Synchronize with the camera */
 	ret = ucam3_sync();
 	if (ret) {

samples/camera/src/ucam3.c

@@ -10,6 +10,7 @@
 #include <misc/byteorder.h>
 #include <string.h>
 #include <stdbool.h>
+#include <gpio.h>
 
 #define CAM_UART_NAME DT_UART_STM32_USART_2_NAME
 
@@ -34,6 +35,8 @@ static struct {
 } cam_data;
 
 static struct tty_serial cam;
+static struct device *reset;
+
 
 typedef enum {
 	ACK_INITIAL,
@@ -107,11 +110,8 @@ static void print_cmd(uint8_t *cmd, int size)
 
 void ucam3_reset(void)
 {
-	uint8_t b;
-
-	while (tty_read(&cam, &b, 1) > 0) {
-		continue;
-	}
+	gpio_pin_write(reset, 3, 0);
+	gpio_pin_write(reset, 3, 1);
 }
 
 int ucam3_sync(void)
@@ -529,5 +529,13 @@ int ucam3_create(void)
 	tty_set_rx_buf(&cam, cam_rxbuf, sizeof(cam_rxbuf));
 	tty_set_rx_timeout(&cam, 250);
 
+	reset = device_get_binding("GPIOA");
+	if (!reset) {
+		return -1;
+	}
+
+	gpio_pin_configure(reset, 3, GPIO_DIR_OUT);
+    // ucam3_reset();
+
 	return 0;
 }

samples/camera/src/ucam3.h

@@ -135,9 +135,9 @@ extern int ucam3_get_picture(u8_t *data, u32_t *size);
 /**
  * @brief Reset the uCAM-III
  *
- * Initialize the serial interface with the camera module.
+ * Hardware reset the module.
  *
- * @retval 0 on success, otherwise -1
+ * @retval none
  */
 extern void ucam3_reset(void);