[经验分享] 【2024 DigiKey 创意大赛】开发板读取D6T传感器值、LVGL显示

pomin 2024-10-31 23:37 楼主

为了把 D6T 传感器连接到开发板，先查看原理图，开发板有一些预留的 IO 接口，但是大多数都不能随意使用

然后查看原理图可以知道 IO47 和 IO48 这两个引脚是作为了 IIC 使用，外接的是屏幕板的电容触摸芯片 FT5406，在代码中也可以看到：

然后查了查文档，FT5406 的 IIC 七位地址是 0x38，而 D6T 的 IIC 七位地址是 0x0A，所以可以把这两个器件都接在 IO47、IO48，然后把 D6T 模块接在开发板的 IO47、IO48上面，代码如下

```c
/*
 * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: CC0-1.0
 */

#include "core/lv_disp.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_check.h"
#include "nvs_flash.h"
#include "nvs.h"

#include "bsp_board_extra.h"
#include "bsp/esp-bsp.h"
#include <stdio.h>
#include <string.h>

#include "driver/i2c.h"

static char *TAG = "app_main";

#define LOG_MEM_INFO  (0)

/* defines */
#define D6T_ADDR 0x0A// for I2C 7bit address
#define D6T_CMD 0x4C // for D6T-44L-06/06H, D6T-8L-09/09H, for D6T-1A-01/02

#define N_ROW 1
#define N_PIXEL 1
#define N_READ ((N_PIXEL + 1) * 2 + 1)

uint8_t rbuf[N_READ];
double ptat;
double pix_data[N_PIXEL];

uint8_t calc_crc(uint8_t data) {
  int index;
  uint8_t temp;
  for (index = 0; index < 8; index++) {
  temp = data;
  data <<= 1;
  if (temp & 0x80) { data ^= 0x07; }
  }
  return data;
}

/**  D6T PEC(Packet Error Check) calculation.
 * calculate the data sequence,
 * from an I2C Read client address (8bit) to thermal data end.
 */
bool D6T_checkPEC(uint8_t buf[], int n) {
  int i;
  uint8_t crc = calc_crc((D6T_ADDR << 1) | 1);// I2C Read address (8bit)
  for (i = 0; i < n; i++) {
  crc = calc_crc(buf<i> ^ crc);
  }
  bool ret = crc != buf[n];
  if (ret) {
  printf("PEC check failed:");
  }
  return ret;
}

/**  convert a 16bit data from the byte stream.
 */
int16_t conv8us_s16_le(uint8_t* buf, int n) {
  uint16_t ret;
  ret = (uint16_t)buf[n];
  ret += ((uint16_t)buf[n + 1]) << 8;
  return (int16_t)ret; // and convert negative.
}

void d6t_1a_01_read(void) {
  int i = 0;
  int16_t itemp = 0;
  uint8_t txbuf[16];

memset(rbuf, 0, N_READ);
  txbuf[0] = D6T_CMD;

i2c_master_write_read_device(CONFIG_BSP_I2C_NUM, D6T_ADDR, txbuf, 1, rbuf, N_READ, 100 / portTICK_PERIOD_MS);

//Convert to temperature data (degC)
  ptat = (double)conv8us_s16_le(rbuf, 0) / 10.0;
  for (i = 0; i < N_PIXEL; i++) {
  itemp = conv8us_s16_le(rbuf, 2 + 2 * i);
  pix_data<i> = (double)itemp / 10.0;
  }

//Output results
  printf("PTAT: %f", ptat);
  printf(" [degC], Temperature: ");
  for (i = 0; i < N_PIXEL; i++) {
  printf("%f , ", pix_data<i>);
  }
  printf(" [degC]\r\n");
}

void app_main(void)
{
  ESP_LOGI(TAG, "Compile time: %s %s", __DATE__, __TIME__);

bsp_i2c_init();
  while (1) {
  d6t_1a_01_read();
  vTaskDelay(pdMS_TO_TICKS(5000));
  }
}
```

然后使用 idf 烧录到开发板，并打开串口监控

```
idf.py flash -p /dev/ttyUSB0 -b 460800 && idf.py monitor -p /dev/ttyUSB0 -b 115200
```

可以看到已经成功读取到了 D6T 传感器的温度值了，然后把这个数据用 LVGL 来显示，在 idf.py menuconfig 中配置好 LVGL 后编写代码

```c
/*
 * SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
 *
 * SPDX-License-Identifier: CC0-1.0
 */

#include "core/lv_disp.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_check.h"
#include "nvs_flash.h"
#include "nvs.h"

#include "bsp_board_extra.h"
#include "bsp/esp-bsp.h"
#include "lv_example_pub.h"
#include "lv_demos.h"
#include <stdio.h>
#include <string.h>

#include "driver/i2c.h"
#include "widgets/lv_label.h"

static char *TAG = "app_main";

#define LOG_MEM_INFO  (0)

/* defines */
#define D6T_ADDR 0x0A// for I2C 7bit address
#define D6T_CMD 0x4C // for D6T-44L-06/06H, D6T-8L-09/09H, for D6T-1A-01/02

#define N_ROW 1
#define N_PIXEL 1
#define N_READ ((N_PIXEL + 1) * 2 + 1)

uint8_t rbuf[N_READ];
double ptat;
double pix_data[N_PIXEL];

uint8_t calc_crc(uint8_t data) {
  int index;
  uint8_t temp;
  for (index = 0; index < 8; index++) {
  temp = data;
  data <<= 1;
  if (temp & 0x80) { data ^= 0x07; }
  }
  return data;
}

void d6t_1a_01_read(void) {
  int i = 0;
  int16_t itemp = 0;
  uint8_t txbuf[16];

memset(rbuf, 0, N_READ);
  txbuf[0] = D6T_CMD;

i2c_master_write_read_device(CONFIG_BSP_I2C_NUM, D6T_ADDR, txbuf, 1, rbuf, N_READ, 100 / portTICK_PERIOD_MS);

//Output results
  printf("PTAT: %f", ptat);
  printf(" [degC], Temperature: ");
  for (i = 0; i < N_PIXEL; i++) {
  printf("%f , ", pix_data<i>);
  }
  printf(" [degC]\r\n");
}

void app_main(void)
{
  ESP_LOGI(TAG, "Compile time: %s %s", __DATE__, __TIME__);
  /* Initialize NVS. */
  esp_err_t err = nvs_flash_init();
  if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
  ESP_ERROR_CHECK(nvs_flash_erase());
  err = nvs_flash_init();
  }
  ESP_ERROR_CHECK(err);

bsp_spiffs_mount();

bsp_i2c_init();
  bsp_extra_codec_init();
  bsp_extra_player_init(BSP_SPIFFS_MOUNT_POINT"/mp3");

bsp_display_start();

bsp_display_lock(0);
  lv_style_pre_init();
  lv_obj_t *label = lv_label_create(lv_scr_act());
  // lv_create_home(&main_Layer);
  // lv_demo_benchmark();
  // lv_create_clock(&clock_screen_layer, TIME_ENTER_CLOCK_2MIN);
  bsp_display_unlock();

while (1) {
  lv_label_set_text_fmt(label, "PTAT: %.2f [degC], Temperature: %.2f ,[degC]", ptat, pix_data[0]);
    lv_obj_set_style_text_font(label, &lv_font_montserrat_16, LV_PART_MAIN|LV_STATE_DEFAULT);

d6t_1a_01_read();
  vTaskDelay(pdMS_TO_TICKS(5000));
  }
}

```

然后就可以在屏幕上用 LVGL 显示数据了

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