示例 Applications¶

本页面记录了 Nexus 仓库中包含的示例应用程序。每个示例演示特定功能，并作为构建您自己应用程序的参考。

所有示例都位于仓库的 applications/ 目录中。

概述¶

Nexus 仓库包含以下示例应用程序：

示例 Applications¶
示例	目的	Key 特性
blinky	基本 GPIO 控制	LED 闪烁、GPIO 初始化、HAL 基础
config_demo	配置 management	配置存储、命名空间、导入/导出、UART 输出
freertos_demo	使用 OSAL 的多任务	任务、互斥锁、信号量、队列、生产者-消费者模式
shell_demo	命令行界面	Shell 命令、UART CLI、命令注册、行编辑

Blinky 示例¶

位置：applications/blinky/

描述：一个简单的 LED 闪烁应用程序，演示基本的 GPIO 控制和 HAL 初始化。

特性¶

HAL 系统初始化
GPIO 配置为输出
LED 顺序闪烁
使用 LED 指示器的错误处理

Hardware 要求¶

STM32F4 Discovery board (or compatible)
LEDs on PD12 (Green), PD13 (Orange), PD14 (Red), PD15 (Blue)

构建和运行¶

# Configure for STM32F4
CMake -B build-stm32f4 \
    -DCMAKE_TOOLCHAIN_FILE=CMake/toolchains/arm-none-eabi.CMake \
    -DNEXUS_PLATFORM=stm32f4

# Build
CMake --build build-stm32f4 --target blinky

# Flash
openocd -f interface/stlink.cfg -f target/stm32f4x.cfg \
    -c "program build-stm32f4/applications/blinky/blinky.elf verify reset exit"

预期行为¶

STM32F4 Discovery 板上的所有四个 LED 按顺序闪烁：

Green LED toggles (500ms)
Orange LED toggles (500ms)
Red LED toggles (500ms)
Blue LED toggles (500ms)
重复

关键代码部分¶

LED 初始化：

static hal_status_t led_init(void) {
    hal_gpio_config_t config = {
        .direction = HAL_GPIO_DIR_OUTPUT,
        .pull = HAL_GPIO_PULL_NONE,
        .output_mode = HAL_GPIO_OUTPUT_PP,
        .speed = HAL_GPIO_SPEED_LOW,
        .init_level = HAL_GPIO_LEVEL_LOW
    };

    /* Initialize all LEDs */
    hal_gpio_init(LED_GREEN_PORT, LED_GREEN_PIN, &config);
    hal_gpio_init(LED_ORANGE_PORT, LED_ORANGE_PIN, &config);
    hal_gpio_init(LED_RED_PORT, LED_RED_PIN, &config);
    hal_gpio_init(LED_BLUE_PORT, LED_BLUE_PIN, &config);

    return HAL_OK;
}

主循环：

while (1) {
    hal_gpio_toggle(LED_GREEN_PORT, LED_GREEN_PIN);
    hal_delay_ms(BLINK_DELAY_MS);

    hal_gpio_toggle(LED_ORANGE_PORT, LED_ORANGE_PIN);
    hal_delay_ms(BLINK_DELAY_MS);

    hal_gpio_toggle(LED_RED_PORT, LED_RED_PIN);
    hal_delay_ms(BLINK_DELAY_MS);

    hal_gpio_toggle(LED_BLUE_PORT, LED_BLUE_PIN);
    hal_delay_ms(BLINK_DELAY_MS);
}

学习成果¶

学习此示例后，您将理解：

如何初始化 HAL 子系统
如何将 GPIO 引脚配置为输出
如何控制 LED 状态
如何使用 HAL 延迟函数
基本错误处理模式

Config Demo 示例¶

位置：applications/config_demo/

描述：演示用于存储和检索配置数据的配置管理器中间件。

特性¶

配置存储和检索
Multiple data types (int32, uint32, float, bool, string, blob)
命名空间隔离
配置查询和枚举
JSON 导入/导出
二进制导入/导出
用于演示的 UART 输出

Hardware 要求¶

STM32F4 Discovery 板
USB-to-Serial adapter connected to UART2 (PA2/PA3)
115200 波特率的串口终端

构建和运行¶

# Configure for STM32F4
CMake -B build-stm32f4 \
    -DCMAKE_TOOLCHAIN_FILE=CMake/toolchains/arm-none-eabi.CMake \
    -DNEXUS_PLATFORM=stm32f4

# Build
CMake --build build-stm32f4 --target config_demo

# Flash
openocd -f interface/stlink.cfg -f target/stm32f4x.cfg \
    -c "program build-stm32f4/applications/config_demo/config_demo.elf verify reset exit"

预期行为¶

应用程序运行多个演示：

基本配置：存储和检索各种数据类型
Namespaces: Demonstrates namespace isolation (WiFi and BLE configs)
查询：列出所有配置条目
JSON 导出/导入：将配置导出为 JSON 并重新导入
二进制导出/导入：将配置导出为二进制格式并重新导入

就绪时绿色 LED 点亮，完成时缓慢闪烁。

关键代码部分¶

Basic 配置 Storage:

/* Store different data types */
config_set_i32("app.timeout", 5000);
config_set_u32("app.retry", 3);
config_set_float("sensor.threshold", 25.5f);
config_set_bool("feature.enabled", true);
config_set_str("device.name", "Nexus-Demo");

/* Read values back */
int32_t timeout = 0;
config_get_i32("app.timeout", &timeout, 0);

命名空间使用：

/* Open namespaces */
config_ns_handle_t wifi_ns, ble_ns;
config_open_namespace("wifi", &wifi_ns);
config_open_namespace("ble", &ble_ns);

/* Store WiFi settings */
config_ns_set_str(wifi_ns, "ssid", "MyNetwork");
config_ns_set_bool(wifi_ns, "auto_connect", true);

/* Close namespaces */
config_close_namespace(wifi_ns);
config_close_namespace(ble_ns);

JSON 导出：

/* Export to JSON */
char buffer[1024];
size_t actual_size = 0;
config_status_t status = config_export(CONFIG_FORMAT_JSON, 0, buffer,
                                       sizeof(buffer), &actual_size);

学习成果¶

学习此示例后，您将理解：

如何初始化和使用配置管理器
如何存储和检索不同的数据类型
如何使用命名空间进行配置隔离
如何导出和导入配置
如何查询配置条目
如何使用 UART 进行调试输出

FreeRTOS Demo 示例¶

位置：applications/freertos_demo/

描述：演示使用带有 FreeRTOS 后端的 OSAL 进行多任务处理。

特性¶

多个并发任务
任务优先级和调度
用于资源保护的互斥锁
用于任务同步的信号量
用于任务间通信的消息队列
生产者-消费者模式
系统统计跟踪

Hardware 要求¶

支持 FreeRTOS 的 STM32F4 Discovery 板
用于视觉反馈的 LED

构建和运行¶

# Configure for STM32F4 with FreeRTOS
CMake -B build-stm32f4 \
    -DCMAKE_TOOLCHAIN_FILE=CMake/toolchains/arm-none-eabi.CMake \
    -DNEXUS_PLATFORM=stm32f4 \
    -DNEXUS_OSAL_BACKEND=FreeRTOS

# Build
CMake --build build-stm32f4 --target freertos_demo

# Flash
openocd -f interface/stlink.cfg -f target/stm32f4x.cfg \
    -c "program build-stm32f4/applications/freertos_demo/freertos_demo.elf verify reset exit"

预期行为¶

应用程序创建四个任务：

Producer Task: Generates sensor data every 100ms, sends to queue
Consumer Task: Receives data from queue, processes it
LED Task: Blinks green LED as heartbeat (500ms)
Stats Task: Periodically reports system statistics (2s)

LED Indicators:

Green: Heartbeat (system running)
Orange: Consumer processing data
Blue: Producer sending data
Red: Queue overflow or error

关键代码部分¶

Task Creation:

/* Producer task - Normal priority */
osal_task_config_t producer_config = {
    .name = "Producer",
    .func = producer_task,
    .arg = NULL,
    .priority = OSAL_TASK_PRIORITY_NORMAL,
    .stack_size = TASK_STACK_SIZE
};
osal_task_create(&producer_config, &g_producer_task);

Message Queue:

/* Create message queue for sensor data */
osal_queue_create(sizeof(sensor_data_t), SENSOR_QUEUE_SIZE,
                 &g_sensor_queue);

/* Send to queue */
osal_queue_send(g_sensor_queue, &data, 10);

/* Receive from queue */
osal_queue_receive(g_sensor_queue, &data, OSAL_WAIT_FOREVER);

Mutex Protection:

/* Create mutex */
osal_mutex_create(&g_stats_mutex);

/* Lock mutex */
if (osal_mutex_lock(g_stats_mutex, 100) == OSAL_OK) {
    /* Critical section - update shared statistics */
    g_stats.samples_produced++;
    osal_mutex_unlock(g_stats_mutex);
}

Semaphore Signaling:

/* Create semaphore */
osal_sem_create_counting(SENSOR_QUEUE_SIZE, 0, &g_data_ready_sem);

/* Signal data ready */
osal_sem_give(g_data_ready_sem);

/* Wait for data */
osal_sem_take(g_data_ready_sem, 500);

学习成果¶

学习此示例后，您将理解：

How to initialize OSAL and create tasks
How to use task priorities
How to protect shared resources with mutexes
How to synchronize tasks with semaphores
How to pass messages between tasks with queues
How to implement producer-consumer patterns
How to start the RTOS scheduler

Shell Demo 示例¶

位置：applications/shell_demo/

Description: Demonstrates the Shell/CLI middleware for interactive command-line interfaces.

特性¶

Interactive command-line interface over UART
Custom command registration
Command parsing and execution
Command completion
Built-in commands (help, version, etc.)
LED control commands
System commands (tick, delay, reboot)

Hardware 要求¶

STM32F4 Discovery 板
USB-to-Serial adapter connected to UART2 (PA2/PA3)
115200 波特率的串口终端

构建和运行¶

# Configure for STM32F4
CMake -B build-stm32f4 \
    -DCMAKE_TOOLCHAIN_FILE=CMake/toolchains/arm-none-eabi.CMake \
    -DNEXUS_PLATFORM=stm32f4

# Build
CMake --build build-stm32f4 --target shell_demo

# Flash
openocd -f interface/stlink.cfg -f target/stm32f4x.cfg \
    -c "program build-stm32f4/applications/shell_demo/shell_demo.elf verify reset exit"

预期行为¶

After flashing, open a serial terminal and you'll see:

========================================
  Nexus Shell Demo v1.0.0
  STM32F4 Discovery Board
  Type 'help' for available commands
========================================
nexus>

可用 Commands:

help - Show available commands
led <color> <on|off|toggle> - Control LEDs (green, orange, red, blue, all)
button - Read user button status
tick - Show system tick count
delay <ms> - Delay for specified milliseconds
reboot - Reboot the system

示例 Session:

nexus> help
Available commands:
  help     - Show this help
  led      - Control LEDs on the board
  button   - Read user button status
  tick     - Show system tick count
  delay    - Delay for specified milliseconds
  reboot   - Reset system

nexus> led green on
LED green ON

nexus> tick
System tick: 12345 ms

nexus> button
User button: RELEASED

关键代码部分¶

Command Handler:

static int cmd_led(int argc, char* argv[]) {
    if (argc < 3) {
        shell_printf("Usage: led <color> <on|off|toggle>\n");
        return 1;
    }

    const char* color = argv[1];
    const char* action = argv[2];

    /* Determine which LED and perform action */
    if (strcmp(action, "on") == 0) {
        hal_gpio_write(port, pin, HAL_GPIO_LEVEL_HIGH);
        shell_printf("LED %s ON\n", color);
    }

    return 0;
}

Command Registration:

static const shell_command_t cmd_led_def = {
    .name = "led",
    .handler = cmd_led,
    .help = "Control LEDs on the board",
    .usage = "led <color> <on|off|toggle>",
    .completion = led_color_completion
};

/* Register command */
shell_register_command(&cmd_led_def);

Shell Initialization:

/* Configure shell */
shell_config_t config = {
    .prompt = "nexus> ",
    .cmd_buffer_size = 128,
    .history_depth = 16,
    .max_commands = 32
};

/* Initialize shell */
shell_init(&config);

/* Set UART backend */
shell_set_backend(&shell_uart_backend);

/* Register commands */
shell_register_builtin_commands();
shell_register_command(&cmd_led_def);

学习成果¶

学习此示例后，您将理解：

How to initialize the Shell framework
How to register custom commands
How to parse command arguments
How to implement command handlers
How to use UART for interactive CLI
How to provide command completion
How to integrate shell with your application

Building All 示例¶

To build all examples at once:

# Configure
CMake -B build-stm32f4 \
    -DCMAKE_TOOLCHAIN_FILE=CMake/toolchains/arm-none-eabi.CMake \
    -DNEXUS_PLATFORM=stm32f4

# Build all examples
CMake --build build-stm32f4 --target all

Example binaries will be located in:

build-stm32f4/applications/blinky/blinky.elf
build-stm32f4/applications/config_demo/config_demo.elf
build-stm32f4/applications/freertos_demo/freertos_demo.elf
build-stm32f4/applications/shell_demo/shell_demo.elf

Modifying 示例¶

All examples are designed to be easily modified and extended:

Copy the Example: Copy the example directory to create your own application
Modify CMakeLists.txt: Update project name and dependencies
Modify main.c: Add your custom functionality
Build and Test: Build and flash to your hardware

Example: Creating a Custom Application from Blinky¶

# Copy blinky example
cp -r applications/blinky applications/my_app

# Edit CMakeLists.txt
# Change: project(blinky C)
# To:     project(my_app C)

# Edit main.c with your custom code

# Build
CMake --build build-stm32f4 --target my_app

故障排除¶

Example doesn't build:

Ensure you have the correct toolchain installed
Check that the platform is set correctly (-DNEXUS_PLATFORM=stm32f4)
Verify all dependencies are available

Example doesn't run after flashing:

Check that you flashed the correct .elf file
Verify the board is powered correctly
Try resetting the board
Check LED indicators for error states

UART examples show no output:

Verify UART wiring (TX/RX crossed correctly)
Check baud rate matches (115200)
Ensure correct COM port is selected in terminal
Try a different USB-to-Serial adapter

FreeRTOS example crashes:

Increase task stack sizes if needed
Check for stack overflow
Verify FreeRTOS is configured correctly

下一步¶

Try modifying the examples to add your own features
Combine concepts from multiple examples
Create your own application based on these examples
Explore the 硬件抽象层 (HAL) and 操作系统抽象层 (OSAL) for more advanced features

Nexus 嵌入式平台

导航

Related Topics

示例 Applications¶

概述¶

Blinky 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

Config Demo 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

FreeRTOS Demo 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

相关文档¶

Shell Demo 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

相关文档¶

Building All 示例¶

Modifying 示例¶

Example: Creating a Custom Application from Blinky¶

故障排除¶

下一步¶

示例 Applications¶

概述¶

Blinky 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

相关教程¶

Config Demo 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

相关文档¶

FreeRTOS Demo 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

相关文档¶

Shell Demo 示例¶

特性¶

Hardware 要求¶

构建和运行¶

预期行为¶

关键代码部分¶

学习成果¶

相关文档¶

Building All 示例¶

Modifying 示例¶

Example: Creating a Custom Application from Blinky¶

故障排除¶

下一步¶