51 单片机实战教程(13 外围芯片驱动程序之CS1237芯片驱动)

        CS1237芯片是一枚国产24位A/D转换芯片，输出速率可选：10Hz、40Hz、640Hz、1.28kHz。内置时钟电路，不需外部晶振。带可编程PGA，PGA放大倍数可选：1、2、64、128。2 线 SPI通信接口，最快速率为 1.1MHz。供电电压：5V/3.3V。芯片应用场合：工业过程控制、电子秤、血压计、智能变换器、便携式设备等。

          CS1237采用SOP8封装，Pin脚定义如下：

       CS1237 SPI  串口通信

其基本时序如图所示：

CS1237读取数据时序图1：

CS1237读取数据时序图 2：

 读取数据时序表：

功能配置：

SPI命令字：

 CS1237有 2 个命令字，命令字的长度为 7bits，命令字描述如下：

CS1237命令字说明表：

CS1237 Config寄存器：

有了这些，就可以写CS1237的驱动库函数了。新建两个文件分别以cs1237.h，cs1237.c存入C51 Template文件夹下Library文件夹中。完成后的头文件如下：

/*cs1237.h
  Designed by Bill Liu
  Version 0.0 
  Modified last by Bill Liu on 12/10/2021
*/
#ifndef __CS1237_H__
#define __CS1237_H__

#include "mtype.h"
#include "delay.h"
#include "myport.h"    //CS1237_SCLK and CS1237_DOUT were defined

extern FSYSCLOCK FSCLK;
//************************************************************************************************************
typedef enum
{
	C1237_10HZ = 0,
	C1237_40HZ = 1,
	C1237_640HZ = 2,
	C1237_1280HZ = 3
}C1237_SPEED;

//************************************************************************************************************
typedef enum
{
	C1237_PGA_1 = 0,
	C1237_PGA_2 = 1,
	C1237_PGA_64 = 2,
	C1237_PGA_128 = 3
}C1237_PGA;

//************************************************************************************************************
typedef enum
{
	C1237_CHA = 0, //adc channel
	C1237_RST = 1, //cheap reserved
	C1237_TEM = 2, //temperature test
	C1237_INS = 3 //internal short
}C1237_CHN;

/************************************************************************************************************
Function: C1237_InClk();
Return value: void
Discription: C1237 input a clk pusle for to read or write
Example:
  C1237_InClk();
*************************************************************************************************************/
void C1237_InClk();

/************************************************************************************************************
Function: CS1237_ReadReg();
Return value: ui8
Discription: read CS1237 register
Example:
  CS1237_ReadReg();
*************************************************************************************************************/
ui8 CS1237_ReadReg();

/************************************************************************************************************
Function: C1237_WriteReg(ui8 mData);
Return value: void
Discription: wreite data to C1237 register
Example:
  C1237_WriteReg(mData);
*************************************************************************************************************/
void C1237_WriteReg(ui8 mData);

/************************************************************************************************************
Function: C1237_Init(BOOL refOutable,C1237_SPEED msel,C1237_PGA mselPga,C1237_CHN mselChn);
Return value: void
Discription: CS1237 init
Example:
  C1237_Init(0,C1237_10HZ,C1237_PGA_1,C1237_CHA);//ref voltage out disable,speed 10Hz,Pga 1, work at Adc mode
*************************************************************************************************************/
void C1237_Init(BOOL refOutable,C1237_SPEED msel,C1237_PGA mselPga,C1237_CHN mselChn);

/************************************************************************************************************
Function: C1237_ReadResult();
Return value: ui32
Discription: read C1237 A/D result
Example:
  C1237_ReadResult();
*************************************************************************************************************/
ui32 C1237_ReadResult();

#endif

完成后的源代码如下：

/*cs1237.c
  Designed by Bill Liu
  Version 0.0 
  Modified last by Bill Liu on 12/10/2021
*/

#include "cs1237.h"

//*************************************************************************************************************
void C1237_InClk()
{
  CS1237_SCLK= 1;
  Delayxus(2,FSCLK); 
  CS1237_SCLK = 0;
  Delayxus(2,FSCLK); 
}
//End of C1237_InClk()

//*************************************************************************************************************
ui8 CS1237_ReadReg() 
{
  ui8 i = 0;
	ui8 tem = 0;
  while(i <27) // the 27 clks at the beginning of configure function time sequential
  {
    C1237_InClk();
    i++;
  }
  CS1237_DOUT = 1; //force high
  i = 0;
  while(i < 3)     // 28~30th clks
  {
    C1237_InClk();
    i++;
  }
  i = 0;
  tem = 0x56;     //command of reading CS1237_register
  while(i < 7)    //31~37th clk,write command
  {
    if(tem &0x40)     //begine from MSB
      CS1237_DOUT = 1;
    else 
      CS1237_DOUT = 0;
    C1237_InClk();
    tem <<= 1;
    i++;
  }
  i = 0;
  tem = 0;
  while(i < 8)  //38~45th clk, read data from CS1237_register
  {
     tem <<= 1;
    C1237_InClk();
    if( CS1237_DOUT)  //read data
     tem += 1;        
    i++;
  }
  C1237_InClk();  //46th clk
  return tem;
}
//End of CS1237_ReadReg()

//*************************************************************************************************************
void C1237_WriteReg(ui8 mData)
{
  ui8 i = 0;
	ui8 tem = 0;
  while(i < 27) // the 27 clks at the beginning of configure function time sequential
  {
    C1237_InClk();
    i++;
  }
  CS1237_DOUT = 1; //force high
  i = 0;
  while(i < 3)     // 28~30th clks
  {
    C1237_InClk();
    i++;
  }
  i = 0;
  tem = 0x65;     //command of writing CS1237_register
  while(i < 7)    //31~37th clk,write command
  {
    if(tem &0x40)     //begine from MSB
      CS1237_DOUT = 1;
    else 
      CS1237_DOUT = 0;
    C1237_InClk();
    tem <<= 1;
    i++;
  }
  i = 0;
  while(i < 8)  //38~45th clk, write data to CS1237_register
  {
    if(mData &0x80)     //begine from MSB
      CS1237_DOUT = 1;
    else 
      CS1237_DOUT = 0;
    C1237_InClk();
    mData <<= 1;
    i++;
  }
  C1237_InClk(); //46th clk
}
//End of C1237_WriteReg(ui8 mData)

//*************************************************************************************************************
void C1237_Init(BOOL refOutable,C1237_SPEED msel,C1237_PGA mselPga,C1237_CHN mselChn)
{
  ui8 tem = 0;
  if(refOutable)
    ResetBit(&tem, 0);
  else
    SetBit(&tem, 0);
  SetBits(&tem,5,4,msel);
  SetBits(&tem,3,2,mselPga);
  SetBits(&tem,1,0,mselChn);
  C1237_WriteReg(tem);
}
//End of C1237_Init(BOOL refOutable,C1237_SPEED msel,C1237_PGA mselPga,C1237_CHN mselChn) 

//*************************************************************************************************************
ui32 C1237_ReadResult()
{
  ui8 i;
	ui32 rdata = 0;
  CS1237_SCLK= 0;
  while(CS1237_DOUT);          //waite ADC finish
  for(i = 0; i < 24; i++)
  {
    rdata <<= 1;
    C1237_InClk();
    if(CS1237_DOUT) //read data
      rdata += 1;
  }
  C1237_InClk();
  C1237_InClk();
  C1237_InClk();
  return rdata;
}
//End of C1237_ReadResult()

受一些因素影响，可能个别ADC数据不是很准确，需要消除或减小其影响，我们可以采用多值平均法，阀值剔除法等数字滤波手法，有了以上库函数就可以轻松实现。具体做法，这里不做演示，在后面的开发工程实战教程中将会看到。本教程的源码及CS1237的 datasheet 已一并打包上传到CSDN，如需离线查看，文件名为CS1237 Diver Code & Datasheet.rar， 可搜索下载。