MSP430杂谈--AD7793硬件SPI驱动与模拟SPI驱动

最近项目中用到了AD7793读取铂电阻值来得到相应的温度，编写了基于MSP430的硬件驱动程序和模拟驱动程序，并且能成功运行，现在记录一下分享给大家。

AD7793硬件IIC驱动完整版下载链接：https://download.csdn.net/download/qq_42580947/11041933

AD7793模拟IIC驱动完整版下载链接：https://download.csdn.net/download/qq_42580947/11041961

PS：目前资源积分无法自行调整，有谁知道可以修改积分的方法请告知，我想免费分享给大家。

1. AD7793硬件SPI驱动

单片机型号为：MSP430F57XX

硬件SPI驱动失败的几个原因有：单片机配置SPI资源错误（包括SPI的时钟，SPI的运行模型等配置错误），单片机的系统时钟配置错误（注意MCLK, SMCLK, ACLK的分配）

1.1 SPI read with AD7793

/******************** SPI read with AD7793 ***********************/

void AD7793_R(unsigned char addr, unsigned char *buffer, int n)

{

  unsigned int index;

  unsigned char temp;

  AD7793_CS_DIS;

  __delay_cycles(200); 

  AD7793_CS_EN;

  // t1>0ns

  __delay_cycles(200); 

  // send address

  while(!(UCB0IFG & UCTXIFG));              

    UCB0TXBUF = addr;

  while(!(UCB0IFG & UCRXIFG));            

    temp = UCB0RXBUF;

  // Delay > 10us, after writing to RAM

  Delay10us(2);  

  // Read data from register and load in buffer[]

  for(index=0; index < n; index++)

  {

    while(!(UCB0IFG & UCTXIFG));              

    UCB0TXBUF = 0x00;

    while(!(UCB0IFG & UCRXIFG));            

    buffer[index] = UCB0RXBUF;

    Delay10us(100);

  }

  AD7793_CS_DIS;

}

1.2 SPI write with AD7793

/******************** SPI write with AD7793 ***********************/

void AD7793_W(unsigned char addr, unsigned char *buffer, char n)

{

  unsigned char index;

  AD7793_CS_EN;

  // t1>0ns

  __delay_cycles(200); 

  // send address

  while(!(UCB0IFG & UCTXIFG));              

  UCB0TXBUF = addr;

  // Delay > 10us, after writing to RAM

  Delay10us(2);  

  // Read data from register and load in buffer[]

  for(index=0; index < n; index++)

  {

    while(!(UCB0IFG & UCTXIFG));            

    UCB0TXBUF = buffer[index];

  }

   AD7793_CS_DIS;  

}

1.3 AD7793 相关寄存器配置

/******************** AD7793 Configuration ***********************/

void AD7793_CON(void)

{

  AD7793_CS_EN;

  //single model

  SPI_Data[0] = 0x20;

  //64k intenal CLK，4.17Hz update rate（stable time 500ms）

  SPI_Data[1] = 0x0f;                   

  //Model regeister

  AD7793_W(0x08, SPI_Data, 2);

  AD7793_CS_DIS;  

}

1.4 电压测量

/******************** voltage measurement ***********************/

void V_measure (void)

{

 /*** Read the both sides voltage of RTD ***/

  //bioplar encoding, 8 times, input range 312.5mV

  //external reference voltage, buffer mode, AIN1 input

  AD7793_CON();

  SPI_Data[0] = 0x03;

  SPI_Data[1] = 0x10;                     

  AD7793_W(0x10, SPI_Data, 2);

  //IEXC1,IEXC2 connected with IOUT1，current is 210uA

  //IO register

  SPI_Data[0] = 0x0E;

  AD7793_W(0x28, SPI_Data, 1);

  //data register

  AD7793_R(0x58, SPI_Data, 3);

  //get the temperature values

  ad_result_T = SPI_Data[0];

  ad_result_T <<= 8;

  ad_result_T += SPI_Data[1];

  ad_result_T <<= 8;

  ad_result_T += SPI_Data[2];

  ad_result_T &= 0x00ffffff;

  ad_result_T -= 8388608;

  T =(float)ad_result_T*3.7104E-5;

 /*** Read the ambient temperature ***/

  //bioplar encoding, 8 times, input range 312.5mV

  //external reference voltage, buffer mode, AIN1 input

  SPI_Data[0] = 0x00;

  SPI_Data[1] = 0x86;                     

  AD7793_W(0x10, SPI_Data, 2);

  //data register

  AD7793_R(0x58, SPI_Data, 3);

  //get the ambient temperature

  ad_result_T1 = SPI_Data[0];

  ad_result_T1 <<= 8;

  ad_result_T1 += SPI_Data[1];

  ad_result_T1 <<= 8;

  ad_result_T1 += SPI_Data[2];

  ad_result_T1 &= 0x00ffffff;

  ad_result_T1 -= 8388608;

  Tenvir =(float)ad_result_T1*3.7104E-5;

}

2. AD7793模拟SPI驱动

模拟SPI驱动失败的最主要原因是：时钟！时钟！时钟！注意时钟的配置和延时的处理

2.1 AD7793基础子函数的处理

void AD7793_CS_SET()//CS置1

{

    P1OUT |= BIT1; 

}

void AD7793_CS_CLR()//CS置0

{

    P1OUT &=~ BIT1; 

}

void AD7793_SCLK_SET()

{

    P2OUT |= BIT2; 

}

void AD7793_SCLK_CLR()

{

    P2OUT &=~ BIT2; 

} 

void AD7793_DIN_SET()

{

    P1OUT |= BIT6;

}

void AD7793_DIN_CLR()

{

    P1OUT &=~ BIT6;

}

unsigned int AD7793_DOUT_GET()

{

    unsigned int i;

    if(P1IN & BIT7)

      i = 1;

    else

      i = 0;

    return i;

}

2.2 向AD7793写入一个字节

void WriteToReg(unsigned char ByteData) //向AD7793写入一个字节

{

    unsigned char temp;

    unsigned char i;

    AD7793_CS_CLR();

    AD7793_SCLK_SET();

    temp=0x80;

    for(i=0;i<8;i++)

    {

        if((temp & ByteData)==0)

        {

            AD7793_DIN_CLR();

        }

        else

        {

            AD7793_DIN_SET();

        }

        AD7793_SCLK_CLR();

        Delay();

        AD7793_SCLK_SET();

        Delay();

        temp=temp>>1;

    }

    AD7793_CS_SET();

}

2.3 复位AD7793

void AD7793_Reset(void)//AD7793复位

{

    P1DIR |= BIT6;      

    P2DIR |= BIT2;

    P1DIR &=~ BIT7;

    unsigned int ResetTime;

    ResetTime = 32;

    AD7793_SCLK_SET();

    AD7793_CS_CLR();

    AD7793_DIN_SET();

    while(ResetTime--)

    {

        Delay();

        AD7793_SCLK_CLR();

        Delay();

        AD7793_SCLK_SET();

    }

    AD7793_CS_SET();

}

2.4 读取AD7793

unsigned char AD7793_ReadStatusRegister(void) //读取7793的状态寄存器

{

    unsigned char j;

    unsigned char temp;

    WriteToReg(0x40);

    AD7793_DIN_SET();

    AD7793_CS_CLR();

    temp=0;

    for(j=0; j<8; j++)

    {

        AD7793_SCLK_CLR();

        if(AD7793_DOUT_GET()==0)

        {

            temp=temp<<1;

        }

        else

        {

            temp=temp<<1;

            temp=temp+0x01;

        }

        Delay();

        AD7793_SCLK_SET();

        Delay();

    }

    AD7793_CS_SET();

    return temp;

}

2.5 配置相关寄存器

void Ad7793_WriteModeRegister(unsigned char ModeRegisterH,unsigned char ModeRegisterL)

//配置模式寄存器

{

    WriteToReg(0x08);

    WriteToReg(ModeRegisterH);

    WriteToReg(ModeRegisterL);

}

void Ad7793_WriteConfigRegister(unsigned char ConfigRegisterH,unsigned char ConfigRegisterL)

//配置配置寄存器

{

    WriteToReg(0x10);

    WriteToReg(ConfigRegisterH);

    WriteToReg(ConfigRegisterL);

}

void Ad7793_WriteIORegister(unsigned char IORegister)

//配置IO寄存器

{

    WriteToReg(0x28);

    WriteToReg(IORegister);

}

2.6 读取AD7793数据寄存器

long AD7793_ReadDataRegister(void)

{

union

{

    unsigned char chardata[3];

    unsigned long longdata;

}AD7793Result;

    unsigned char i,j;

    unsigned char temp;

    temp=AD7793_ReadStatusRegister();

    while((temp&0x80)==0x80)

    {

        temp=AD7793_ReadStatusRegister();

    }

    WriteToReg(0x58);

    AD7793_DIN_SET();

    AD7793_CS_CLR();

    for(i=0; i<3; i++)

    {

        for(j=0; j<8; j++)

        {

            AD7793_SCLK_CLR();

            if(AD7793_DOUT_GET()==0)

            {

                temp=temp<<1;

            }

            else

            {

                temp=temp<<1;

                temp=temp+0x01;

            }

        Delay();

        AD7793_SCLK_SET();

        Delay();

        }

        AD7793Result.chardata[3-i]=temp;

    }

    AD7793_CS_SET();

    AD7793Result.longdata=AD7793Result.longdata>>8;

    return AD7793Result.longdata;

}

2.7 初始化AD7793

void Init_AD7793(void)//AD7793的初始化

{

    AD7793_CS_SET();

    AD7793_Reset();

    Ad7793_WriteModeRegister(0x00,0x0F);//连续转换

    Ad7793_WriteConfigRegister(0x03,0x10);//292.5mv，1.65V偏压

    Ad7793_WriteIORegister(0x0E);

}