硬件修改

多圈绝对值功能需要用一个3.6V的电池接到伺服电机编码器上来实现断电保存多圈数据。电池淘宝地址(带安装座)

清除多圈数据得到初始原点：

把PR15的参数设置为0：

多圈绝对值通讯

STM32主要程序232通讯

u8 UART5_RX_BUF[20];    //接收缓冲,最大20个字节，用于储存编码器位置信息
u8 U5_i=0; 
struct _code
{
    u32 code_value;//编码器值
    u32 cylinder_number;//圈数
    u8 check_bit;//校验位
};

//编码器通讯串口5初始化。伺服驱动默认是9600，可修改pr5.29改变
void SERVO_CODE_Init(u32 bound)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
     
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_GPIOD, ENABLE);  //使能UART5，GPIOC、GPIOD时钟
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART5, ENABLE);
  
    //UART5_TX   GPIOC.12初始化
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12; //PC.12
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出
    GPIO_Init(GPIOC, &GPIO_InitStructure);//初始化GPIOC.12
   
    //UART5_RX    GPIOD.2初始化
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;//PD.2
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入
    GPIO_Init(GPIOD, &GPIO_InitStructure);//初始化GPIOD.2  

    //UART5 NVIC 配置
    NVIC_InitStructure.NVIC_IRQChannel = UART5_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;//抢占优先级1
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;      //子优先级0
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;         //IRQ通道使能
    NVIC_Init(&NVIC_InitStructure); //根据指定的参数初始化VIC寄存器
  
   //USART 初始化设置
    USART_InitStructure.USART_BaudRate = bound;//串口波特率
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字长为8位数据格式
    USART_InitStructure.USART_StopBits = USART_StopBits_1;//一个停止位
    USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流控制
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //收发模式

    USART_Init(UART5, &USART_InitStructure); //初始化串口5
    USART_ITConfig(UART5, USART_IT_RXNE, ENABLE);//开启串口接受中断
    USART_Cmd(UART5, ENABLE);                    //使能串口5                
}


//从串口5发送一个字节的函数
void UART5_SendByte(u8 k)
{
    USART_SendData(UART5, k);
    while(USART_GetFlagStatus(UART5,USART_FLAG_TC)!=SET);//等待发送结束
}


//串口5中断，把伺服编码器的值返回到UART5_RX_BUF[]数组中
void UART5_IRQHandler(void)
{
    u8 Res;
    if(USART_GetITStatus(UART5, USART_IT_RXNE) != RESET)  //接收中断
    {
        Res =USART_ReceiveData(UART5);//(UART5->DR);    //读取接收到的数据
        UART5_RX_BUF[U5_i]=Res;
        U5_i++;     
        if(U5_i>=20)
        {U5_i=0;}
    }
}

//获得圈数和编码值
struct _code Get_Code(void)
{
    struct _code CODE;
    CODE.check_bit = 0;//校验位初始化
    U5_i = 0;
    UART5_SendByte(0x05);
    nopdelay_ms(4);
    UART5_SendByte(0x00);
    UART5_SendByte(0x01);
    UART5_SendByte(0xD2);
    UART5_SendByte(0x2D);
    nopdelay_ms(4);
    UART5_SendByte(0x04);
    nopdelay_ms(4);
    UART5_SendByte(0x06);
    //编码值   
    CODE.code_value = (u32)(UART5_RX_BUF[10]+UART5_RX_BUF[11]*0x100+UART5_RX_BUF[12]*0x10000);//低位+中位*0x100+高位*0x10000
    //圈数
    CODE.cylinder_number = UART5_RX_BUF[13]+UART5_RX_BUF[14]*0x100;
    if(CODE.cylinder_number <= 32767)
        CODE.cylinder_number = CODE.cylinder_number + 65536;//32768~65535为负，65536~98303为正,65536为原点
    
    if((UART5_RX_BUF[0]!=0x04)|(UART5_RX_BUF[1]!=0x06)|(UART5_RX_BUF[2]!=0x05)|(UART5_RX_BUF[3]!=0x0B))
    {
        CODE.code_value = 0x00800000;//读数失败时，返回8388608
        CODE.check_bit = 1;//失败
    }
    U5_i = 0;
    return CODE;
}