[求助] stm32F429用模拟IIC驱动AD5933测量人体阻抗小阻抗），写入寄存器后读出的都是FF求解

麻辣鸡丶 2020-5-21 15:20 楼主

代码：

void SetPointer(char nAddr) // 设置地址指针
{
   int nTemp = 0x1A; // AD5933的默认地址&写控制位（低）

IIC_Start();
   IIC_Send_Byte(nTemp); // 发送地址
   IIC_Wait_Ack(); // 等待 ACK

IIC_Send_Byte(0xB0); // 发送指针命令1101 0000
IIC_Wait_Ack();

IIC_Send_Byte(nAddr); // 发送地址指针
IIC_Wait_Ack();

IIC_Stop();// 停止总线
    return;
}
u16 AD5933_ReadOneByte(u16 ReadAddr)
{
       u16 temp;
       SetPointer(ReadAddr);
       temp=0x1B;
IIC_Start();

       IIC_Send_Byte(temp); //发送器件地址0XA0,写数据
       IIC_Wait_Ack();

       temp=IIC_Read_Byte(0);
       IIC_Wait_Ack();

IIC_Stop();//产生一个停止条件
       delay_ms(10);
       return temp;

}

void AD5933_WriteOneByte(u8 WriteAddr,u16 DataToWrite)
{
           int Temp = 0x1A;
           IIC_Start();
           IIC_Send_Byte(Temp); //发送器件地址0X1A,写数据
           IIC_Wait_Ack();

           IIC_Send_Byte(WriteAddr); //发送地址
           IIC_Wait_Ack();

           IIC_Send_Byte(DataToWrite); //发送字节
           IIC_Wait_Ack();
   //printf("IIC_Wait_Ack：%d\n",IIC_Wait_Ack());
           IIC_Stop();//产生一个停止条件
           delay_ms(10);
}

void AD5933_Init(void)
{
   delay_ms(5);
   //写入扫描频率10KHz
   AD5933_WriteOneByte(0x82,0x04); //起始频率
   delay_ms(5);
   AD5933_WriteOneByte(0x83,0xE2); //10kHz
   AD5933_WriteOneByte(0x84,0x18);
   //写入频率增量0.5Hz
   AD5933_WriteOneByte(0x85,0x00); //频率增量
   AD5933_WriteOneByte(0x86,0x00); //0.5Hz
   AD5933_WriteOneByte(0x87,0x10);
   //写入增量2
   AD5933_WriteOneByte(0x88,0x00); //增量数
   AD5933_WriteOneByte(0x89,0x02); //2点

   //写入控制寄存器设置参数
   AD5933_WriteOneByte(0x80,0xB1); //将AD5933置于待机模式 ,输出电压范围：典型值2.0Vpp;PGA增益:*1
   AD5933_WriteOneByte(0x81,0x00); //选择内部系统时钟MCLK=16．776MHZ
   AD5933_WriteOneByte(0x81,0x10); //Reset
   AD5933_WriteOneByte(0x81,0x00);
   //初始化起始频率（用开始频率初始化）

   AD5933_WriteOneByte(0x80,0x11);
   delay_ms(5);
   //建立等待周期数
   AD5933_WriteOneByte(0x8A,0x02); //时间循环周期
   AD5933_WriteOneByte(0x8B,0x08); //16个周期
   delay_ms(5);
//启动频率扫描
   AD5933_WriteOneByte(0x80,0x21);

}

void AD5933GetImpedance(void)
{
       //printf("0x82: %x\n",AD5933_ReadOneByte(0x84));
       AD5933_Init();
   //   delay_ms(10);
       //AD5933_WriteOneByte(0x89,0x02);
       printf("0x89: %x\n",AD5933_ReadOneByte(0x89));
       printf("0x82: %x\n",AD5933_ReadOneByte(0x82));
       //printf("before:\n",AD5933_ReadOneByte(0x80));
// printf("after: %x\n",AD5933_ReadOneByte(0x80));

IIC用的正点原子的例程：void IIC_Start(void)
{
   SDA_OUT(); //sda线输出
   IIC_SDA=1;
   IIC_SCL=1;
   delay_us(4);
    IIC_SDA=0;//START:when CLK is high,DATA change form high to low
   delay_us(4);
   IIC_SCL=0;//钳住I2C总线，准备发送或接收数据
}
//产生IIC停止信号
void IIC_Stop(void)
{
   SDA_OUT();//sda线输出
   IIC_SCL=0;
   IIC_SDA=0;//STOP:when CLK is high DATA change form low to high
    delay_us(4);
   IIC_SCL=1;
   delay_us(4);
   IIC_SDA=1;//发送I2C总线结束信号
}
//等待应答信号到来
//返回值：1，接收应答失败
// 0，接收应答成功
u8 IIC_Wait_Ack(void)
{
   u8 ucErrTime=0;
   SDA_IN(); //SDA设置为输入
   IIC_SDA=1;delay_us(1);
   IIC_SCL=1;delay_us(1);
   while(READ_SDA)
   {
       ucErrTime++;
       if(ucErrTime>250)
       {
           IIC_Stop();
           return 1;
       }
   }
   IIC_SCL=0;//时钟输出0
   return 0;
}
//产生ACK应答
void IIC_Ack(void)
{
   IIC_SCL=0;
   SDA_OUT();
   IIC_SDA=0;
   delay_us(2);
   IIC_SCL=1;
   delay_us(2);
   IIC_SCL=0;
}
//不产生ACK应答
void IIC_NAck(void)
{
   IIC_SCL=0;
   SDA_OUT();
   IIC_SDA=1;
   delay_us(2);
   IIC_SCL=1;
   delay_us(2);
   IIC_SCL=0;
}
//IIC发送一个字节
//返回从机有无应答
//1，有应答
//0，无应答
void IIC_Send_Byte(u16 txd)
{
u16 t;
   SDA_OUT();
IIC_SCL=0;//拉低时钟开始数据传输
for(t=0;t<8;t++)
{
IIC_SDA=(txd&0x80)>>7;
txd<<=1;
       delay_us(2); //对TEA5767这三个延时都是必须的
       IIC_SCL=1;
       delay_us(2);
       IIC_SCL=0;
       delay_us(2);
}
}
//读1个字节，ack=1时，发送ACK，ack=0，发送nACK
u8 IIC_Read_Byte(unsigned char ack)
{
   unsigned char i,receive=0;
   SDA_IN();//SDA设置为输入
for(i=0;i<8;i++ )
   {
IIC_SCL=0;
delay_us(2);
       IIC_SCL=1;
receive<<=1;
if(READ_SDA)receive++;
       delay_us(1);
}
if (!ack)
IIC_NAck();//发送nACK
else
IIC_Ack(); //发送ACK
return receive;
}