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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();
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