UWB开发板项目实践分享

项目背景

原本的任务是用UWB技术，根据手机的方位信息来改变开发板上RGB LED灯的颜色和亮度。但在开发过程中，我发现芯片不支持AOA（到达角）功能，导致无法获取手机角度信息，原任务没法完成。后来，我调整了任务目标：用屏幕显示手机到UWB开发板的距离，并根据距离信息改变开发板上LED灯的状态。

硬件介绍

• SSD1306 OLED 0.96 寸屏幕 ：通过I2C通讯，用于显示距离信息。
• DWM3001CDK 开发板 ：基于Qorvo DW3110 IC的全集成UWB模块开发套件，能和Apple U1、U2芯片一起用。
• iPhone 11 ：支持UWB功能的手机，用来和开发板配合。

软件流程及核心代码

初始化与任务创建

在主函数里，我初始化了软i2c、log输出、UWB模块等，还创建了FreeRTOS任务和队列。为啥要创建队列和OLED显示任务呢？因为如果在蓝牙的回调函数里更新屏幕显示，软i2c更新时间会影响蓝牙通讯，导致蓝牙断开连接。

/**@brief Function for application main entry.
 */
int main(void) {
  // Initialize modules.
  clock_init();
  reporter_instance.init();
  hal_uwb.mcu_sleep_config();
#if NRF_LOG_ENABLED
  init_logger_thread();
#endif
  // Accessory Nearby Interaction Initialization
  niq_init(ResumeUwbTasks,
           StopUwbTask,
           (const void *)nrf_crypto_init,
           (const void *)nrf_crypto_uninit,
           (const void *)nrf_crypto_rng_vector_generate);
  // Accessory instructed to act as a Responder or Initiator
  niq_set_ranging_role(ACCESSORY_RANGING_ROLE);
  // Create Default task: it responsible for WDT and starting of "applications"
  AppConfigInit(); /**< load the RAM Configuration parameters from NVM block */
  // Start BLE
  char advertising_name[32];
  snprintf(advertising_name,
           sizeof(advertising_name),
           "%s (%08X)",
           (char *)BoardName,
           (unsigned int)NRF_FICR->DEVICEADDR[0]);
  ble_init(advertising_name);
  EventManagerInit();
  BoardInit();
  if (uwb_init() != DWT_SUCCESS) {
    APP_ERROR_HANDLER(NRF_ERROR_RESOURCES)
  }
  DefaultTaskInit();
  // Driver version is available after probing of the DW chip
  const char ver[]    = FULL_VERSION;
  const char *drv_ver = dwt_version_string();
  const char *mac_ver = uwbmac_get_version();
  char str[256];
  int sz;
  sz = sprintf(str, "Application: %s\r\n", ApplicationName);
  sz += sprintf(&str[sz], "BOARD: %s\r\n", BoardName);
  sz += sprintf(&str[sz], "OS: %s\r\n", OsName);
  sz += sprintf(&str[sz], "Version: %s\r\n", ver);
  sz += sprintf(&str[sz], "%s\r\n", drv_ver);
  sz += sprintf(&str[sz], "MAC: %s\r\n", mac_ver);
  sz += sprintf(&str[sz], "ACCESSORY_RANGING_ROLE: %s\r\n", (ACCESSORY_RANGING_ROLE) ? "Initiator" : "Responder");
  reporter_instance.print(str, sz);
  I2C_Init();
  OLED_Init();
  xQueue = xQueueCreate(10, sizeof(int));
  xTaskCreate(vTask1, "Task1", configMINIMAL_STACK_SIZE, NULL, 1, NULL);
  // Start FreeRTOS scheduler.
  osKernelStart();
  for (;;) {
    APP_ERROR_HANDLER(NRF_ERROR_FORBIDDEN);
  }
}

OLED显示任务

这个任务从队列里接收数据，然后把距离信息刷新到屏幕上，这样就不会干扰蓝牙协议了。

void vTask1(void *pvParameters) {
  char *buff = "AppInit: Initializing application...\n";
  // 应用程序启动时的初始化逻辑
  reporter_instance.print(buff, strlen(buff));
  Testing_Display();
  while (1) {
    int received_value;
    if (xQueueReceive(xQueue, &received_value, portMAX_DELAY) == pdPASS) {
      Testing_Display5(received_value);
    }
    vTaskDelay(pdMS_TO_TICKS(200));
  }
}

蓝牙回调函数

拿到手机与开发板之间的距离信息后，我对数据进行归一化处理，根据不同的距离区间控制不同的LED灯点亮或熄灭。

///定义灯的状态
int led_states[8][4] = {
    {0, 1, 1, 1}, 
    {0, 1, 1, 1}, 
    {0, 0, 1, 1}, 
    {0, 0, 1, 1}, 
    {0, 0, 0, 1}, 
    {0, 0, 0, 1}, 
    {0, 0, 0, 0}, 
    {0, 0, 0, 0}  
    };
// 定义每个条件对应的LED状态
void set_leds(const int* states) {
    for (int i = 0; i < 4; i++) {
        if (states[i]) {
            bsp_board_led_on(i);
        } else {
            bsp_board_led_off(i);
        }
    }
}
/*
 * @brief   Gets the ranging results and print it
 * */
static void report_cb(const struct ranging_results *results, void *user_data) {

  static bool notify = true;
  int len = 0;
  int distance_cm;
  struct string_measurement *str_result = (struct string_measurement *)user_data;
  struct ranging_measurements *rm;
  fira_param_t *fira_param = get_fira_config();
  if (results->stopped_reason != 0xFF)
    return;
  session_id = fira_param->session_id;
  len = sprintf(str_result->str, "{\"Block\":%" PRIu32 ", \"results\":[", results->block_index);
  for (int i = 0; i < results->n_measurements; i++) {
    if (i > 0) {
      len += snprintf(&str_result->str[len], str_result->len - len, ",");
    }
    rm = (struct ranging_measurements *)(&results->measurements[i]);
    len += snprintf(&str_result->str[len],
                    str_result->len - len,
                    "{\"Addr\":\"0x%04x\",\"Status\":\"%s\"",
                    rm->short_addr,
                    (rm->status) ? ("Err") : ("Ok"));
    if (rm->status == 0) {
      distance_cm = (int)rm->distance_mm / 10;
      xQueueSend(xQueue, &distance_cm, pdMS_TO_TICKS(5)); // 发送数据到队列
    int condition = distance_cm / 10;
    // 检查条件是否在范围内
    if (condition >= 0 && condition < 8) {
        set_leds(led_states[condition]); ///设置灯
    } else {
        // 默认情况，开启所有LED
        for (int i = 0; i < 4; i++) {
            bsp_board_led_on(i);
        }
    }
      len += snprintf(&str_result->str[len], str_result->len - len, ",\"D_cm\":%d", (int)rm->distance_mm / 10);
      if (hal_uwb.is_aoa() == AOA_ENABLED) {
        len += snprintf(&str_result->str[len],
                        str_result->len - len,
                        ",\"LPDoA_deg\":%0.2f,\"LAoA_deg\":%0.2f,\"LFoM\":%d,\"RAoA_deg\":%0.2f",
                        convert_aoa_2pi_q16_to_deg(rm->local_aoa_measurements[0].pdoa_2pi),
                        convert_aoa_2pi_q16_to_deg(rm->local_aoa_measurements[0].aoa_2pi),
                        rm->local_aoa_measurements[0].aoa_fom,
                        convert_aoa_2pi_q16_to_deg(rm->remote_aoa_azimuth_2pi));
      }
      len += snprintf(
          &str_result->str[len], str_result->len - len, ",\"CFO_100ppm\":%d", (int)fira_uwb_mcps_get_cfo_ppm());
      // Take action based on distance
      if (notify && (distance_cm < MIN_CM_DISTANCE_THRESHOLD)) {
#if LEDS_NUMBER > 1
        // Visual indication on the device for "inside the bubble"
        bsp_board_led_on(BSP_BOARD_LED_2);     // Red LED On
        bsp_board_led_off(BSP_BOARD_LED_0);    // Green LED Off
#endif
        // Send message to trigger notification on the iOS side
        send_ios_notification((uint8_t)distance_cm, "You are in the secure bubble.");
        notify = false;
      } else if (!notify && (distance_cm > MAX_CM_DISTANCE_THRESHOLD)) {
#if LEDS_NUMBER > 1
        // Visual indication on the device for "outside the bubble"
        bsp_board_led_off(BSP_BOARD_LED_2);    // Red LED Off
        bsp_board_led_on(BSP_BOARD_LED_0);     // Green LED On
#endif
        // Send message to trigger notification on the iOS side
        send_ios_notification((uint8_t)distance_cm, "You are out of the secure bubble.");
        notify = true;
      }
    }
    len += snprintf(&str_result->str[len], str_result->len - len, "}");
  }
  len += snprintf(&str_result->str[len], str_result->len - len, "]");
  /* Display RSSI, CFO and NLOS */
  if (fira_uwb_is_diag_enabled()) {
    len = fira_uwb_add_diag(str_result->str, len, str_result->len);
  }
  len += snprintf(&str_result->str[len], str_result->len - len, "}\r\n");
  reporter_instance.print((char *)str_result->str, len);
}

功能展示：连接蓝牙根据返回距离信息点亮不同的led灯

• ：返回距离为0的时候，点亮是所有LED灯-
• 距离小于20大于10的时候，点亮是三个LED灯：
• 大于30的时候点亮两个LED：
• 大于40的时候，所有LED都不点亮
  

项目中的难题与解决方法

• AOA功能问题 ：一开始我不清楚开发板没开启AOA信息，后来还是在朋友的王哥帮助下，才找到AOA的初始化信息。因为他踩过坑了，所以问了下他，他说他踩过坑，所以知道了AOA的初始化信息
• I2C屏幕刷新问题 ：在使用屏幕显示的时候，用过彩屏和OLED，SSD1306没反应，最后没法想到是硬I2C 用的不对，只能用软I2C。
• 蓝牙的数据回调：找了很久才找到蓝牙的数据回调方法在哪里。

心得体会

这次活动让我非常感谢主办方提供的宝贵机会，让我得以接触到DWM3001CDK板卡，并亲身体验UWB技术的魅力。这是我第一次接触UWB（超宽带）定位技术，而这次实践让我对它的潜力有了更深刻的认识。尤其是测距的精准度，远超我的预期，误差几乎可以忽略不计，UWB之前一直都在苹果AirTag上有而已，这让我对UWB技术的实际应用充满期待。最后，再次感谢活动方提供的这次宝贵机会，让我能够在实践中学习和成长。未来，我期待UWB技术的进一步普及