esp32cam ov5640 例子

下面是ESP32-CAM使用OV5640摄像头的例程：

#include "esp_camera.h"
#include "esp_log.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "nvs_flash.h"
#include "soc/soc.h"
#include "soc/rtc_cntl_reg.h"
#include "driver/gpio.h"

static const char *TAG = "example";

static void wifi_init_sta()
{
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    esp_wifi_init(&cfg);
    esp_wifi_set_storage(WIFI_STORAGE_RAM);
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = "YOUR_SSID",
            .password = "YOUR_PASSWORD",
        },
    };
    esp_wifi_set_mode(WIFI_MODE_STA);
    esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config);
    esp_wifi_start();
}

void app_main()
{
    nvs_flash_init();
    wifi_init_sta();

    // set up OV5640 camera
    camera_config_t config = {
        .pin_pwdn = -1,
        .pin_reset = -1,
        .pin_xclk = 32,
        .pin_sscb_sda = 26,
        .pin_sscb_scl = 27,

        .pin_d7 = 35,
        .pin_d6 = 34,
        .pin_d5 = 39,
        .pin_d4 = 36,
        .pin_d3 = 21,
        .pin_d2 = 19,
        .pin_d1 = 18,
        .pin_d0 = 5,

        .pin_vsync = 25,
        .pin_href = 23,
        .pin_pclk = 22,

        .xclk_freq_hz = 20000000,
        .ledc_timer = LEDC_TIMER_0,
        .ledc_channel = LEDC_CHANNEL_0,
        .pixel_format = PIXFORMAT_JPEG,
        .frame_size = FRAMESIZE_QVGA,
        .jpeg_quality = 12,
        .fb_count = 1
    };
    esp_err_t err = esp_camera_init(&config);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Camera init failed with error 0x%x", err);
        return;
    }

    // take a picture
    camera_fb_t *fb = esp_camera_fb_get();
    if (!fb) {
        ESP_LOGE(TAG, "Camera capture failed");
        return;
    }

    // do something with the picture
    // ...

    // release the picture
    esp_camera_fb_return(fb);

    // disable the camera
    esp_camera_deinit();
}

需要注意的是，该例程使用了ESP32的Wi-Fi功能，需要在代码中修改为自己的Wi-Fi SSID和密码。此外，还需要在`sdkconfig.h`文件中启用`CONFIG_ESP32_CAMERA`选项。