写一段代码，使STM32单片机AD信号采集发送给手机APP

好的，下面是一段使用STM32单片机采集ADC信号并通过蓝牙发送给手机APP的代码示例，仅供参考：

#include "stm32f10x.h"
#include "stm32f10x_usart.h"
#include "stm32f10x_adc.h"
#include "stm32f10x_dma.h"
#include "stm32f10x_gpio.h"

// 定义USART1的GPIO引脚
#define USART1_GPIO GPIOA
#define USART1_TX_PIN GPIO_Pin_9
#define USART1_RX_PIN GPIO_Pin_10

// 定义ADC采样的GPIO引脚
#define ADC_GPIO GPIOA
#define ADC_PIN GPIO_Pin_0

// 定义蓝牙模块的USART引脚
#define BLUETOOTH_USART USART2
#define BLUETOOTH_USART_GPIO GPIOA
#define BLUETOOTH_USART_TX_PIN GPIO_Pin_2
#define BLUETOOTH_USART_RX_PIN GPIO_Pin_3

// 定义DMA缓存区大小
#define DMA_BUFFER_SIZE 4

// 定义DMA缓存区
uint16_t dma_buffer[DMA_BUFFER_SIZE];

// 初始化USART1，用于调试输出
void init_usart1()
{
    // 使能USART1时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
    
    // 配置USART1 GPIO引脚
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = USART1_TX_PIN | USART1_RX_PIN;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(USART1_GPIO, &GPIO_InitStructure);
    
    // 配置USART1
    USART_InitTypeDef USART_InitStructure;
    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);
    
    // 使能USART1
    USART_Cmd(USART1, ENABLE);
}

// 初始化ADC1，用于采集信号
void init_adc1()
{
    // 使能ADC1时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
    
    // 配置ADC1 GPIO引脚
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = ADC_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(ADC_GPIO, &GPIO_InitStructure);
    
    // 配置ADC1
    ADC_InitTypeDef ADC_InitStructure;
    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
    ADC_InitStructure.ADC_ScanConvMode = DISABLE;
    ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_NbrOfChannel = 1;
    ADC_Init(ADC1, &ADC_InitStructure);
    
    // 配置ADC采样通道
    ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_28Cycles5);
    
    // 使能ADC1
    ADC_Cmd(ADC1, ENABLE);
    
    // 配置DMA
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
    DMA_InitTypeDef DMA_InitStructure;
    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&ADC1->DR;
    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)dma_buffer;
    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
    DMA_InitStructure.DMA_BufferSize = DMA_BUFFER_SIZE;
    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
    DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
    DMA_Init(DMA1_Channel1, &DMA_InitStructure);
    
    // 使能DMA
    DMA_Cmd(DMA1_Channel1, ENABLE);
    
    // 开始转换
    ADC_SoftwareStartConvCmd(ADC1, ENABLE);
}

// 初始化USART2，用于蓝牙通信
void init_usart2()
{
    // 使能USART2时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
    
    // 配置USART2 GPIO引脚
    GPIO_InitTypeDef GPIO_InitStructure;
    GPIO_InitStructure.GPIO_Pin = BLUETOOTH_USART_TX_PIN | BLUETOOTH_USART_RX_PIN;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_Init(BLUETOOTH_USART_GPIO, &GPIO_InitStructure);
    
    // 配置USART2
    USART_InitTypeDef USART_InitStructure;
    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
    USART_Init(BLUETOOTH_USART, &USART_InitStructure);
    
    // 使能USART2
    USART_Cmd(BLUETOOTH_USART, ENABLE);
}

// 将ADC采样值转换为字符串
void convert_adc_value_to_string(char* string, uint16_t value)
{
    sprintf(string, "%d", value);
}

int main()
{
    // 初始化USART1、ADC1和USART2
    init_usart1();
    init_adc1();
    init_usart2();
    
    // 定义变量
    char string[16];
    uint16_t adc_value;
    
    while(1)
    {
        // 获取DMA缓存区中的ADC采样值
        adc_value = dma_buffer[0];
        
        // 将ADC采样值转换为字符串
        convert_adc_value_to_string(string, adc_value);
        
        // 发送字符串到USART1（调试输出）
        USART_SendString(USART1, string);
        
        // 发送字符串到USART2（蓝牙）
        USART_SendString(BLUETOOTH_USART, string);
        
        // 等待一段时间，避免发送过快
        for(int i = 0; i < 1000000; i++);
    }
}

这段代码将ADC采样值通过USART1和蓝牙发送到手机APP。请注意，这里只是一个简单的示例，实际应用中还需要进行一些处理，例如校准、滤波和数据格式化等。