ADS1256驱动程序

1，初始化

接口：
/********************************************
     SPI2           STM32      ADS1256
    
    NSS      --  PB12   --   CS
    SCK      --  PB13   --  SCLK
    MISO    --  PB14   --  DOUT
    MOSI    --  PB15   --  DIN
                       PB10   --  DRDY
             PB11   --  RESET
    
    
********************************************/

2，ADS_sum(a,b)：函数功能，测量电压a-b
          ADS1256_MUXP_AIN（0~7）代表通道0~7，差分正 P：positive
           ADS1256_MUXN_AIN（0~7）代表通道0~7，差分负 N：negative
            
            例：差分测量通道0和1：ADS_sum(ADS1256_MUXP_AIN0 | ADS1256_MUXN_AIN1);    返回通道0-通道1的电压值
                   单端测量通道0：   ADS_sum(ADS1256_MUXP_AIN0 | ADS1256_MUXN_AINCOM);  返回通道0对地的电压值

#include <stdio.h>
#include "stm32f10x_gpio.h"
#include "ADS1256.h"


void SPI2_Init(void)
{
 SPI_InitTypeDef  SPI_InitStructure;
 GPIO_InitTypeDef GPIO_InitStructure;
 /****Initial SPI2******************/
 
 /* Enable SPI2 and GPIOB clocks */
 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
 RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);
 
 

 /* Configure SPI2 pins: NSS, SCK, MISO and MOSI */
 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
 GPIO_Init(GPIOB, &GPIO_InitStructure);
 
 //SPI2 NSS 
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
 
 GPIO_SetBits(GPIOB, GPIO_Pin_12);
 
  /* SPI2 configuration */ 
 SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; 
 SPI_InitStructure.SPI_Mode = SPI_Mode_Master;                    
 SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;                  
 SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;                   
 SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;                 
 SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;                  
 SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; 
 SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;      
 SPI_InitStructure.SPI_CRCPolynomial = 7;       
 SPI_Init(SPI2, &SPI_InitStructure);
 /* Enable SPI2  */
 SPI_Cmd(SPI2, ENABLE);  
}  

//ADS1256 GPIO
void Init_ADS1256_GPIO(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

	RCC_APB2PeriphClockCmd(RCC_ADS1256Reset | RCC_ADS1256DRDY, ENABLE); 

  	GPIO_InitStructure.GPIO_Pin = GPIO_RCC_ADS1256Reset; 
  	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
  	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  
  	GPIO_Init(GPIO_RCC_ADS1256Reset_PORT, &GPIO_InitStructure);  
  	GPIO_ResetBits(GPIO_RCC_ADS1256Reset_PORT, GPIO_RCC_ADS1256Reset );


	GPIO_InitStructure.GPIO_Pin = GPIO_ADS1256DRDY; 
  	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
  	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  
  	GPIO_Init(GPIO_ADS1256DRDY_PORT, &GPIO_InitStructure);  

	SPI2_Init();
}



unsigned char SPI_WriteByte(unsigned char TxData)
{
  unsigned char RxData=0;

  while(SPI_I2S_GetFlagStatus(SPI2,SPI_I2S_FLAG_TXE)==RESET); //                                                   
  SPI_I2S_SendData(SPI2,TxData);

   while(SPI_I2S_GetFlagStatus(SPI2,SPI_I2S_FLAG_RXNE)==RESET);

   RxData=SPI_I2S_ReceiveData(SPI2);

    return RxData;
} 


void ADS1256WREG(unsigned char regaddr,unsigned char databyte)
{
    GPIO_ResetBits(GPIOB, GPIO_Pin_12);
	while(GPIO_ReadInputDataBit(GPIO_ADS1256DRDY_PORT,GPIO_ADS1256DRDY));
	
    SPI_WriteByte(ADS1256_CMD_WREG | (regaddr & 0x0F));
   
    SPI_WriteByte(0x00);
   
    SPI_WriteByte(databyte);
	GPIO_SetBits(GPIOB, GPIO_Pin_12);
}


//ADS1256
void ADS1256_Init(void)
{
	ADS1256WREG(ADS1256_STATUS,0x06);               
//	ADS1256WREG(ADS1256_MUX,0x08);                  
	ADS1256WREG(ADS1256_ADCON,0x00);               
	ADS1256WREG(ADS1256_DRATE,ADS1256_DRATE_10SPS);  
	ADS1256WREG(ADS1256_IO,0x00);               
}


unsigned int ADS1256ReadData()  
{
    unsigned char i=0;
    unsigned int sum=0;
	unsigned int r=0;
	GPIO_ResetBits(GPIOB, GPIO_Pin_12);;

	while(GPIO_ReadInputDataBit(GPIO_ADS1256DRDY_PORT,GPIO_ADS1256DRDY));      

         
//	ADS1256WREG(ADS1256_MUX,channel);		
	SPI_WriteByte(ADS1256_CMD_SYNC);
	SPI_WriteByte(ADS1256_CMD_WAKEUP);	               
	SPI_WriteByte(ADS1256_CMD_RDATA);

   	sum |= (SPI_WriteByte(0xff) << 16);
	sum |= (SPI_WriteByte(0xff) << 8);
	sum |= SPI_WriteByte(0xff);

	GPIO_SetBits(GPIOB, GPIO_Pin_12); 
    return sum;
}



unsigned int ADS_sum(unsigned char channel)
{
	ADS1256WREG(ADS1256_MUX,channel);		
	return ADS1256ReadData();
}

2主函数

int main(void)
{
unsigned char i=0;
long ulResult;
long double ldVolutage;
uart_init(9600);
Init_ADS1256_GPIO(); 
ADS1256_Init();

	while(1)
	{	
		for(i = 0;i < 8;i++)
		{
			 //ulResult = ADS_sum( (i << 4) | ADS1256_MUXN_AINCOM);	  //8路测量时放开
			ulResult = ADS_sum( ADS1256_MUXP_AIN0 | ADS1256_MUXN_AINCOM); //单测0路	
			if( ulResult & 0x800000 )
			{
			 	ulResult = ~(unsigned long)ulResult;
				ulResult &= 0x7fffff;
				ulResult += 1;
				ulResult = -ulResult;
			}
		
			ldVolutage = (long double)ulResult*0.59604644775390625;

		//	printf("第%d路:",(i & 0x07)?(i & 0x07) - 1:7);
			printf("第1路");
			printf("%lf",ldVolutage); 	
			printf("uV\r\n");
                        delay_ms(1000);
			//printf("%x",(unsigned long)ulResult);//16
			Delay(0x3fFFF);
		}
	}
		
 

}

3.中值滤波

#define MEDIAN_LEN  5                     //中直滤波的总长度，一般选取奇数   
#define MEDIAN      2                     //中值在滤波数组中的位置
unsigned long   AD_buffer[MEDIAN_LEN];    //ad采集数组缓存
//unsigned long   MED_buffer[MEDIAN_LEN];   //中值滤波数组缓存
unsigned char   medleng = 0;          //存入缓存的数据个数
/**********************************************************/
// 函数名：中值滤波函数
// 描述  ：提取前9次采集的数据，去掉高3个，去掉低3个，然后中间的
// 描述  ：3个数据求平均值，该算法可尽可能的滤掉干扰数据，并不影响采集速度。
// 输入  ：9个数据的数组
// 输出  ：中间3个数据的平均值
/*********************************************************/
unsigned long medina_filter(unsigned long *MED_buffer)  //xad - ADC转换值   
{   
	
	unsigned char i,j;
	unsigned long xd;
	u32 xxd;
	
	for(i = 0; i < MEDIAN_LEN; i ++)     
	{   
		for(j = 0; j < MEDIAN_LEN - i; j ++)
		{
			
			if( MED_buffer[i] > MED_buffer[i + 1]) // 轮询到的当前元素>AD值,则交换它们的值   
			{ xd = MED_buffer[i]; MED_buffer[i] = MED_buffer[i + 1]; MED_buffer[i + 1] = xd;} 
		}			
	} 
	xxd = MED_buffer[MEDIAN - 1] + MED_buffer[MEDIAN] + MED_buffer[MEDIAN + 1];
	xd = xxd/3;
	return xd; //中值     
}