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TMS320F28335 ADC采样率

2018-01-17 分类：C2000™ 32位实时 MCU 阅读(858)

 

问题概述：ADC配置成同步采样模式，排序器级联，ADC时钟25MHz，采样率12.5MSPS，同步采样A0，B0的模拟信号，A0，B0的模拟信号是信号源输出的1MHz正弦波，采样点512个；

在CCS6.1的Graph中观察到采样的1MHz正弦波信号的采样率根本就不是12.5MSPS，像是100MSPS，而且每个采样点重复采样了4次，使得正弦波出现了阶梯状；

出现的疑问：

1.在这种设置模式下，ADC的采样率到底是多少？

2.每个采样点为什么会重复采样了4次，使得正弦波出现了阶梯状？

以下是我的配置代码，不知道是否有问题，请各位大神帮我看看！！

main.c文件代码：

#include "Fir.h"

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define     LED4 GpioDataRegs.GPADAT.bit.GPIO0

#define     LED3 GpioDataRegs.GPADAT.bit.GPIO1

#define     LED1 GpioDataRegs.GPADAT.bit.GPIO6

#define     LED2 GpioDataRegs.GPADAT.bit.GPIO7

#define     BUZZ_C  GpioDataRegs.GPBSET.bit.GPIO60=1;

#define     BUZZ_O  GpioDataRegs.GPBCLEAR.bit.GPIO60=1;

 

interruptvoidISRExint1(void);

voidconfigtestled(void);

voidInitExInt(void);

 

#if (CPU_FRQ_150MHZ)     // Default – 150 MHz SYSCLKOUT

 #define ADC_MODCLK 0x3 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3)   = 25.0 MHz

#endif

#if (CPU_FRQ_100MHZ)

 #define ADC_MODCLK 0x2 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 100/(2*2)   = 25.0 MHz

#endif

 

#define BUF_SIZE   512  // Sample buffer size

 

// Global variable for this example

Uint16 SampleTable[BUF_SIZE];

Uint16 SampleTable2[BUF_SIZE];

volatile Uint16 ADC_Start = 0;

 

voidmain(void)

{

   Uint16 i;

   Uint16 array_index=0;

 

   InitSysCtrl();

 

   EALLOW;

   SysCtrlRegs.HISPCP.all = ADC_MODCLK;

   EDIS;

   DINT;

 

   InitPieCtrl();

 

   IER = 0x0000;// Disable CPU interrupts and clear all CPU interrupt flags:

   IFR = 0x0000;

 

   InitPieVectTable();

   InitExInt();

   EALLOW;  // This is needed to write to EALLOW protected registers

   PieVectTable.XINT1 = &ISRExint1;

   EDIS;    // This is needed to disable write to EALLOW protected registers

 

   PieCtrlRegs.PIECTRL.bit.ENPIE = 1;          // Enable the PIE block

   PieCtrlRegs.PIEIER1.bit.INTx4= 1;

   IER |= M_INT1;                              // Enable CPU int1

 

   EINT;   // 中断使能

   ERTM;   // Enable Global realtime interrupt DBGM

   configtestled();

   BUZZ_C;//关掉蜂鸣器

 

   InitAdc();         // For this example, init the ADC

// Clear SampleTable

  for (i=0; i<BUF_SIZE; i++)

   {

     SampleTable[i] = 0;

     SampleTable2[i] = 0;

   }

 

   AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 0x1;    //Start-of-conversion (SOC) trigger for Sequencer 1 (SEQ1)

  while(1)

   {

      //if(ADC_Start)

      {

         while(AdcRegs.ADCST.bit.INT_SEQ1 == 0);

          AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;

          SampleTable[array_index] = ((AdcRegs.ADCRESULT0)>>4);

          SampleTable2[array_index] = ((AdcRegs.ADCRESULT1)>>4);

          array_index++;//DELAY_US(1);

         if(array_index > (BUF_SIZE-1))

          {

             ADC_Start = 0;

             array_index =0;

             //LinearConvolution(a,b,Sample,h,y1);//线性卷积

          }

      }

    }

}

 

 

interruptvoidISRExint1(void)

{

   ADC_Start = 1;

    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

}

 

voidInitExInt(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO13 = 0;

   GpioCtrlRegs.GPADIR.bit.GPIO13 = 0;

   GpioCtrlRegs.GPAQSEL1.bit.GPIO13= 0;

   GpioIntRegs.GPIOXINT1SEL.bit.GPIOSEL = 13;//选择GPIO13为外部输入XINT3输入引脚

   XIntruptRegs.XINT1CR.bit.POLARITY= 1;//上升沿触发中断

   XIntruptRegs.XINT1CR.bit.ENABLE = 1; //使能XINT3中断

   EDIS;

}

 

voidconfigtestled(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0; // GPIO0复用为GPIO功能

   GpioCtrlRegs.GPADIR.bit.GPIO0 = 1;  // GPIO0设置为输出

   GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 0; // GPIO1 = GPIO1

   GpioCtrlRegs.GPADIR.bit.GPIO1 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO6 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO6 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO7 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO7 = 1;

   GpioCtrlRegs.GPBMUX2.bit.GPIO60 = 0; //

   GpioCtrlRegs.GPBPUD.bit.GPIO60 = 0;

   GpioCtrlRegs.GPBDIR.bit.GPIO60 = 1;

   EDIS;

}

 

InitAdc.c 文件代码如下：

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define ADC_usDELAY  5000L

#define ADC_CKPS   0x0   // ADC module clock = HSPCLK/1      = 25.5MHz/(1)   = 25.0 MHz

#define ADC_SHCLK  0x0   // S/H width in ADC module periods                  = 1 ADC cycle

 

voidInitAdc(void)

{

   externvoidDSP28x_usDelay(Uint32 Count);

   EALLOW;

   SysCtrlRegs.PCLKCR0.bit.ADCENCLK = 1;

   ADC_cal();

   EDIS;

 

   // Specific ADC setup for this example:

   AdcRegs.ADCTRL1.bit.CPS = 0; //ADCCLK = Prescaled HSPCLK (ADCCLKPS[3:0])

   AdcRegs.ADCTRL1.bit.ACQ_PS = 0; // ADC module clock = HSPCLK/1 = 25MHz

                             // If Simultaneous mode enabled: Sample rate = 1/[(3+ACQ_PS)*ADC clock in ns]

   AdcRegs.ADCTRL1.bit.SEQ_CASC = 1;       // Setup cascaded sequencer mode

   AdcRegs.ADCTRL1.bit.CONT_RUN = 1;       // Setup continuous run

   AdcRegs.ADCTRL1.bit.SEQ_OVRD = 1;       // Enable Sequencer override feature

 

   //AdcRegs.ADCTRL2.bit.RST_SEQ1 =  0x1;   //Immediately reset sequencer to state CONV00

   AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 0x1;//SEQ1 interrupt enable

   AdcRegs.ADCTRL2.bit.INT_MOD_SEQ1 = 0x0;//SEQ1 interrupt mode

 

   AdcRegs.ADCTRL3.bit.ADCCLKPS = 0x0;//HSPCLK

   AdcRegs.ADCTRL3.bit.SMODE_SEL = 0x1; // Setup simultaneous sampling mode

   AdcRegs.ADCTRL3.bit.ADCBGRFDN = 0x3; //The bandgap and reference circuitry is powered up.

   DELAY_US(1);

   AdcRegs.ADCTRL3.bit.ADCPWDN = 0x1;  //The analog circuitry inside the core is powered up

 

   AdcRegs.ADCMAXCONV.bit.MAX_CONV1 = 0x0; // 1 double conv's (2 total)

   AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x0;  // Setup conv from ADCINA0 &amp; ADCINB0

 

    DELAY_US(ADC_usDELAY);         // Delay before converting ADC channels

}

tao yang20：

测试图片在附件中

 

问题概述：ADC配置成同步采样模式，排序器级联，ADC时钟25MHz，采样率12.5MSPS，同步采样A0，B0的模拟信号，A0，B0的模拟信号是信号源输出的1MHz正弦波，采样点512个；

在CCS6.1的Graph中观察到采样的1MHz正弦波信号的采样率根本就不是12.5MSPS，像是100MSPS，而且每个采样点重复采样了4次，使得正弦波出现了阶梯状；

出现的疑问：

1.在这种设置模式下，ADC的采样率到底是多少？

2.每个采样点为什么会重复采样了4次，使得正弦波出现了阶梯状？

以下是我的配置代码，不知道是否有问题，请各位大神帮我看看！！

main.c文件代码：

#include "Fir.h"

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define     LED4 GpioDataRegs.GPADAT.bit.GPIO0

#define     LED3 GpioDataRegs.GPADAT.bit.GPIO1

#define     LED1 GpioDataRegs.GPADAT.bit.GPIO6

#define     LED2 GpioDataRegs.GPADAT.bit.GPIO7

#define     BUZZ_C  GpioDataRegs.GPBSET.bit.GPIO60=1;

#define     BUZZ_O  GpioDataRegs.GPBCLEAR.bit.GPIO60=1;

 

interruptvoidISRExint1(void);

voidconfigtestled(void);

voidInitExInt(void);

 

#if (CPU_FRQ_150MHZ)     // Default – 150 MHz SYSCLKOUT

 #define ADC_MODCLK 0x3 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3)   = 25.0 MHz

#endif

#if (CPU_FRQ_100MHZ)

 #define ADC_MODCLK 0x2 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 100/(2*2)   = 25.0 MHz

#endif

 

#define BUF_SIZE   512  // Sample buffer size

 

// Global variable for this example

Uint16 SampleTable[BUF_SIZE];

Uint16 SampleTable2[BUF_SIZE];

volatile Uint16 ADC_Start = 0;

 

voidmain(void)

{

   Uint16 i;

   Uint16 array_index=0;

 

   InitSysCtrl();

 

   EALLOW;

   SysCtrlRegs.HISPCP.all = ADC_MODCLK;

   EDIS;

   DINT;

 

   InitPieCtrl();

 

   IER = 0x0000;// Disable CPU interrupts and clear all CPU interrupt flags:

   IFR = 0x0000;

 

   InitPieVectTable();

   InitExInt();

   EALLOW;  // This is needed to write to EALLOW protected registers

   PieVectTable.XINT1 = &ISRExint1;

   EDIS;    // This is needed to disable write to EALLOW protected registers

 

   PieCtrlRegs.PIECTRL.bit.ENPIE = 1;          // Enable the PIE block

   PieCtrlRegs.PIEIER1.bit.INTx4= 1;

   IER |= M_INT1;                              // Enable CPU int1

 

   EINT;   // 中断使能

   ERTM;   // Enable Global realtime interrupt DBGM

   configtestled();

   BUZZ_C;//关掉蜂鸣器

 

   InitAdc();         // For this example, init the ADC

// Clear SampleTable

  for (i=0; i<BUF_SIZE; i++)

   {

     SampleTable[i] = 0;

     SampleTable2[i] = 0;

   }

 

   AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 0x1;    //Start-of-conversion (SOC) trigger for Sequencer 1 (SEQ1)

  while(1)

   {

      //if(ADC_Start)

      {

         while(AdcRegs.ADCST.bit.INT_SEQ1 == 0);

          AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;

          SampleTable[array_index] = ((AdcRegs.ADCRESULT0)>>4);

          SampleTable2[array_index] = ((AdcRegs.ADCRESULT1)>>4);

          array_index++;//DELAY_US(1);

         if(array_index > (BUF_SIZE-1))

          {

             ADC_Start = 0;

             array_index =0;

             //LinearConvolution(a,b,Sample,h,y1);//线性卷积

          }

      }

    }

}

 

 

interruptvoidISRExint1(void)

{

   ADC_Start = 1;

    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

}

 

voidInitExInt(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO13 = 0;

   GpioCtrlRegs.GPADIR.bit.GPIO13 = 0;

   GpioCtrlRegs.GPAQSEL1.bit.GPIO13= 0;

   GpioIntRegs.GPIOXINT1SEL.bit.GPIOSEL = 13;//选择GPIO13为外部输入XINT3输入引脚

   XIntruptRegs.XINT1CR.bit.POLARITY= 1;//上升沿触发中断

   XIntruptRegs.XINT1CR.bit.ENABLE = 1; //使能XINT3中断

   EDIS;

}

 

voidconfigtestled(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0; // GPIO0复用为GPIO功能

   GpioCtrlRegs.GPADIR.bit.GPIO0 = 1;  // GPIO0设置为输出

   GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 0; // GPIO1 = GPIO1

   GpioCtrlRegs.GPADIR.bit.GPIO1 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO6 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO6 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO7 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO7 = 1;

   GpioCtrlRegs.GPBMUX2.bit.GPIO60 = 0; //

   GpioCtrlRegs.GPBPUD.bit.GPIO60 = 0;

   GpioCtrlRegs.GPBDIR.bit.GPIO60 = 1;

   EDIS;

}

 

InitAdc.c 文件代码如下：

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define ADC_usDELAY  5000L

#define ADC_CKPS   0x0   // ADC module clock = HSPCLK/1      = 25.5MHz/(1)   = 25.0 MHz

#define ADC_SHCLK  0x0   // S/H width in ADC module periods                  = 1 ADC cycle

 

voidInitAdc(void)

{

   externvoidDSP28x_usDelay(Uint32 Count);

   EALLOW;

   SysCtrlRegs.PCLKCR0.bit.ADCENCLK = 1;

   ADC_cal();

   EDIS;

 

   // Specific ADC setup for this example:

   AdcRegs.ADCTRL1.bit.CPS = 0; //ADCCLK = Prescaled HSPCLK (ADCCLKPS[3:0])

   AdcRegs.ADCTRL1.bit.ACQ_PS = 0; // ADC module clock = HSPCLK/1 = 25MHz

                             // If Simultaneous mode enabled: Sample rate = 1/[(3+ACQ_PS)*ADC clock in ns]

   AdcRegs.ADCTRL1.bit.SEQ_CASC = 1;       // Setup cascaded sequencer mode

   AdcRegs.ADCTRL1.bit.CONT_RUN = 1;       // Setup continuous run

   AdcRegs.ADCTRL1.bit.SEQ_OVRD = 1;       // Enable Sequencer override feature

 

   //AdcRegs.ADCTRL2.bit.RST_SEQ1 =  0x1;   //Immediately reset sequencer to state CONV00

   AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 0x1;//SEQ1 interrupt enable

   AdcRegs.ADCTRL2.bit.INT_MOD_SEQ1 = 0x0;//SEQ1 interrupt mode

 

   AdcRegs.ADCTRL3.bit.ADCCLKPS = 0x0;//HSPCLK

   AdcRegs.ADCTRL3.bit.SMODE_SEL = 0x1; // Setup simultaneous sampling mode

   AdcRegs.ADCTRL3.bit.ADCBGRFDN = 0x3; //The bandgap and reference circuitry is powered up.

   DELAY_US(1);

   AdcRegs.ADCTRL3.bit.ADCPWDN = 0x1;  //The analog circuitry inside the core is powered up

 

   AdcRegs.ADCMAXCONV.bit.MAX_CONV1 = 0x0; // 1 double conv's (2 total)

   AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x0;  // Setup conv from ADCINA0 &amp; ADCINB0

 

    DELAY_US(ADC_usDELAY);         // Delay before converting ADC channels

}

tao yang20：

回复 tao yang20:

TI的技术支持出来解答一下呀，问了好几次问题，一个都没解决的，真不给力啊

 

问题概述：ADC配置成同步采样模式，排序器级联，ADC时钟25MHz，采样率12.5MSPS，同步采样A0，B0的模拟信号，A0，B0的模拟信号是信号源输出的1MHz正弦波，采样点512个；

在CCS6.1的Graph中观察到采样的1MHz正弦波信号的采样率根本就不是12.5MSPS，像是100MSPS，而且每个采样点重复采样了4次，使得正弦波出现了阶梯状；

出现的疑问：

1.在这种设置模式下，ADC的采样率到底是多少？

2.每个采样点为什么会重复采样了4次，使得正弦波出现了阶梯状？

以下是我的配置代码，不知道是否有问题，请各位大神帮我看看！！

main.c文件代码：

#include "Fir.h"

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define     LED4 GpioDataRegs.GPADAT.bit.GPIO0

#define     LED3 GpioDataRegs.GPADAT.bit.GPIO1

#define     LED1 GpioDataRegs.GPADAT.bit.GPIO6

#define     LED2 GpioDataRegs.GPADAT.bit.GPIO7

#define     BUZZ_C  GpioDataRegs.GPBSET.bit.GPIO60=1;

#define     BUZZ_O  GpioDataRegs.GPBCLEAR.bit.GPIO60=1;

 

interruptvoidISRExint1(void);

voidconfigtestled(void);

voidInitExInt(void);

 

#if (CPU_FRQ_150MHZ)     // Default – 150 MHz SYSCLKOUT

 #define ADC_MODCLK 0x3 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3)   = 25.0 MHz

#endif

#if (CPU_FRQ_100MHZ)

 #define ADC_MODCLK 0x2 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 100/(2*2)   = 25.0 MHz

#endif

 

#define BUF_SIZE   512  // Sample buffer size

 

// Global variable for this example

Uint16 SampleTable[BUF_SIZE];

Uint16 SampleTable2[BUF_SIZE];

volatile Uint16 ADC_Start = 0;

 

voidmain(void)

{

   Uint16 i;

   Uint16 array_index=0;

 

   InitSysCtrl();

 

   EALLOW;

   SysCtrlRegs.HISPCP.all = ADC_MODCLK;

   EDIS;

   DINT;

 

   InitPieCtrl();

 

   IER = 0x0000;// Disable CPU interrupts and clear all CPU interrupt flags:

   IFR = 0x0000;

 

   InitPieVectTable();

   InitExInt();

   EALLOW;  // This is needed to write to EALLOW protected registers

   PieVectTable.XINT1 = &ISRExint1;

   EDIS;    // This is needed to disable write to EALLOW protected registers

 

   PieCtrlRegs.PIECTRL.bit.ENPIE = 1;          // Enable the PIE block

   PieCtrlRegs.PIEIER1.bit.INTx4= 1;

   IER |= M_INT1;                              // Enable CPU int1

 

   EINT;   // 中断使能

   ERTM;   // Enable Global realtime interrupt DBGM

   configtestled();

   BUZZ_C;//关掉蜂鸣器

 

   InitAdc();         // For this example, init the ADC

// Clear SampleTable

  for (i=0; i<BUF_SIZE; i++)

   {

     SampleTable[i] = 0;

     SampleTable2[i] = 0;

   }

 

   AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 0x1;    //Start-of-conversion (SOC) trigger for Sequencer 1 (SEQ1)

  while(1)

   {

      //if(ADC_Start)

      {

         while(AdcRegs.ADCST.bit.INT_SEQ1 == 0);

          AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;

          SampleTable[array_index] = ((AdcRegs.ADCRESULT0)>>4);

          SampleTable2[array_index] = ((AdcRegs.ADCRESULT1)>>4);

          array_index++;//DELAY_US(1);

         if(array_index > (BUF_SIZE-1))

          {

             ADC_Start = 0;

             array_index =0;

             //LinearConvolution(a,b,Sample,h,y1);//线性卷积

          }

      }

    }

}

 

 

interruptvoidISRExint1(void)

{

   ADC_Start = 1;

    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

}

 

voidInitExInt(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO13 = 0;

   GpioCtrlRegs.GPADIR.bit.GPIO13 = 0;

   GpioCtrlRegs.GPAQSEL1.bit.GPIO13= 0;

   GpioIntRegs.GPIOXINT1SEL.bit.GPIOSEL = 13;//选择GPIO13为外部输入XINT3输入引脚

   XIntruptRegs.XINT1CR.bit.POLARITY= 1;//上升沿触发中断

   XIntruptRegs.XINT1CR.bit.ENABLE = 1; //使能XINT3中断

   EDIS;

}

 

voidconfigtestled(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0; // GPIO0复用为GPIO功能

   GpioCtrlRegs.GPADIR.bit.GPIO0 = 1;  // GPIO0设置为输出

   GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 0; // GPIO1 = GPIO1

   GpioCtrlRegs.GPADIR.bit.GPIO1 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO6 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO6 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO7 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO7 = 1;

   GpioCtrlRegs.GPBMUX2.bit.GPIO60 = 0; //

   GpioCtrlRegs.GPBPUD.bit.GPIO60 = 0;

   GpioCtrlRegs.GPBDIR.bit.GPIO60 = 1;

   EDIS;

}

 

InitAdc.c 文件代码如下：

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define ADC_usDELAY  5000L

#define ADC_CKPS   0x0   // ADC module clock = HSPCLK/1      = 25.5MHz/(1)   = 25.0 MHz

#define ADC_SHCLK  0x0   // S/H width in ADC module periods                  = 1 ADC cycle

 

voidInitAdc(void)

{

   externvoidDSP28x_usDelay(Uint32 Count);

   EALLOW;

   SysCtrlRegs.PCLKCR0.bit.ADCENCLK = 1;

   ADC_cal();

   EDIS;

 

   // Specific ADC setup for this example:

   AdcRegs.ADCTRL1.bit.CPS = 0; //ADCCLK = Prescaled HSPCLK (ADCCLKPS[3:0])

   AdcRegs.ADCTRL1.bit.ACQ_PS = 0; // ADC module clock = HSPCLK/1 = 25MHz

                             // If Simultaneous mode enabled: Sample rate = 1/[(3+ACQ_PS)*ADC clock in ns]

   AdcRegs.ADCTRL1.bit.SEQ_CASC = 1;       // Setup cascaded sequencer mode

   AdcRegs.ADCTRL1.bit.CONT_RUN = 1;       // Setup continuous run

   AdcRegs.ADCTRL1.bit.SEQ_OVRD = 1;       // Enable Sequencer override feature

 

   //AdcRegs.ADCTRL2.bit.RST_SEQ1 =  0x1;   //Immediately reset sequencer to state CONV00

   AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 0x1;//SEQ1 interrupt enable

   AdcRegs.ADCTRL2.bit.INT_MOD_SEQ1 = 0x0;//SEQ1 interrupt mode

 

   AdcRegs.ADCTRL3.bit.ADCCLKPS = 0x0;//HSPCLK

   AdcRegs.ADCTRL3.bit.SMODE_SEL = 0x1; // Setup simultaneous sampling mode

   AdcRegs.ADCTRL3.bit.ADCBGRFDN = 0x3; //The bandgap and reference circuitry is powered up.

   DELAY_US(1);

   AdcRegs.ADCTRL3.bit.ADCPWDN = 0x1;  //The analog circuitry inside the core is powered up

 

   AdcRegs.ADCMAXCONV.bit.MAX_CONV1 = 0x0; // 1 double conv's (2 total)

   AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x0;  // Setup conv from ADCINA0 &amp; ADCINB0

 

    DELAY_US(ADC_usDELAY);         // Delay before converting ADC channels

}

Jun Zhang10：

回复 tao yang20:

不错

 

问题概述：ADC配置成同步采样模式，排序器级联，ADC时钟25MHz，采样率12.5MSPS，同步采样A0，B0的模拟信号，A0，B0的模拟信号是信号源输出的1MHz正弦波，采样点512个；

在CCS6.1的Graph中观察到采样的1MHz正弦波信号的采样率根本就不是12.5MSPS，像是100MSPS，而且每个采样点重复采样了4次，使得正弦波出现了阶梯状；

出现的疑问：

1.在这种设置模式下，ADC的采样率到底是多少？

2.每个采样点为什么会重复采样了4次，使得正弦波出现了阶梯状？

以下是我的配置代码，不知道是否有问题，请各位大神帮我看看！！

main.c文件代码：

#include "Fir.h"

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define     LED4 GpioDataRegs.GPADAT.bit.GPIO0

#define     LED3 GpioDataRegs.GPADAT.bit.GPIO1

#define     LED1 GpioDataRegs.GPADAT.bit.GPIO6

#define     LED2 GpioDataRegs.GPADAT.bit.GPIO7

#define     BUZZ_C  GpioDataRegs.GPBSET.bit.GPIO60=1;

#define     BUZZ_O  GpioDataRegs.GPBCLEAR.bit.GPIO60=1;

 

interruptvoidISRExint1(void);

voidconfigtestled(void);

voidInitExInt(void);

 

#if (CPU_FRQ_150MHZ)     // Default – 150 MHz SYSCLKOUT

 #define ADC_MODCLK 0x3 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3)   = 25.0 MHz

#endif

#if (CPU_FRQ_100MHZ)

 #define ADC_MODCLK 0x2 // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 100/(2*2)   = 25.0 MHz

#endif

 

#define BUF_SIZE   512  // Sample buffer size

 

// Global variable for this example

Uint16 SampleTable[BUF_SIZE];

Uint16 SampleTable2[BUF_SIZE];

volatile Uint16 ADC_Start = 0;

 

voidmain(void)

{

   Uint16 i;

   Uint16 array_index=0;

 

   InitSysCtrl();

 

   EALLOW;

   SysCtrlRegs.HISPCP.all = ADC_MODCLK;

   EDIS;

   DINT;

 

   InitPieCtrl();

 

   IER = 0x0000;// Disable CPU interrupts and clear all CPU interrupt flags:

   IFR = 0x0000;

 

   InitPieVectTable();

   InitExInt();

   EALLOW;  // This is needed to write to EALLOW protected registers

   PieVectTable.XINT1 = &ISRExint1;

   EDIS;    // This is needed to disable write to EALLOW protected registers

 

   PieCtrlRegs.PIECTRL.bit.ENPIE = 1;          // Enable the PIE block

   PieCtrlRegs.PIEIER1.bit.INTx4= 1;

   IER |= M_INT1;                              // Enable CPU int1

 

   EINT;   // 中断使能

   ERTM;   // Enable Global realtime interrupt DBGM

   configtestled();

   BUZZ_C;//关掉蜂鸣器

 

   InitAdc();         // For this example, init the ADC

// Clear SampleTable

  for (i=0; i<BUF_SIZE; i++)

   {

     SampleTable[i] = 0;

     SampleTable2[i] = 0;

   }

 

   AdcRegs.ADCTRL2.bit.SOC_SEQ1 = 0x1;    //Start-of-conversion (SOC) trigger for Sequencer 1 (SEQ1)

  while(1)

   {

      //if(ADC_Start)

      {

         while(AdcRegs.ADCST.bit.INT_SEQ1 == 0);

          AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;

          SampleTable[array_index] = ((AdcRegs.ADCRESULT0)>>4);

          SampleTable2[array_index] = ((AdcRegs.ADCRESULT1)>>4);

          array_index++;//DELAY_US(1);

         if(array_index > (BUF_SIZE-1))

          {

             ADC_Start = 0;

             array_index =0;

             //LinearConvolution(a,b,Sample,h,y1);//线性卷积

          }

      }

    }

}

 

 

interruptvoidISRExint1(void)

{

   ADC_Start = 1;

    PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;

}

 

voidInitExInt(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO13 = 0;

   GpioCtrlRegs.GPADIR.bit.GPIO13 = 0;

   GpioCtrlRegs.GPAQSEL1.bit.GPIO13= 0;

   GpioIntRegs.GPIOXINT1SEL.bit.GPIOSEL = 13;//选择GPIO13为外部输入XINT3输入引脚

   XIntruptRegs.XINT1CR.bit.POLARITY= 1;//上升沿触发中断

   XIntruptRegs.XINT1CR.bit.ENABLE = 1; //使能XINT3中断

   EDIS;

}

 

voidconfigtestled(void)

{

   EALLOW;

   GpioCtrlRegs.GPAMUX1.bit.GPIO0 = 0; // GPIO0复用为GPIO功能

   GpioCtrlRegs.GPADIR.bit.GPIO0 = 1;  // GPIO0设置为输出

   GpioCtrlRegs.GPAMUX1.bit.GPIO1 = 0; // GPIO1 = GPIO1

   GpioCtrlRegs.GPADIR.bit.GPIO1 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO6 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO6 = 1;

   GpioCtrlRegs.GPAMUX1.bit.GPIO7 = 0; //

   GpioCtrlRegs.GPADIR.bit.GPIO7 = 1;

   GpioCtrlRegs.GPBMUX2.bit.GPIO60 = 0; //

   GpioCtrlRegs.GPBPUD.bit.GPIO60 = 0;

   GpioCtrlRegs.GPBDIR.bit.GPIO60 = 1;

   EDIS;

}

 

InitAdc.c 文件代码如下：

#include "DSP2833x_Device.h"     // DSP2833x Headerfile Include File

#include "DSP2833x_Examples.h"   // DSP2833x Examples Include File

 

#define ADC_usDELAY  5000L

#define ADC_CKPS   0x0   // ADC module clock = HSPCLK/1      = 25.5MHz/(1)   = 25.0 MHz

#define ADC_SHCLK  0x0   // S/H width in ADC module periods                  = 1 ADC cycle

 

voidInitAdc(void)

{

   externvoidDSP28x_usDelay(Uint32 Count);

   EALLOW;

   SysCtrlRegs.PCLKCR0.bit.ADCENCLK = 1;

   ADC_cal();

   EDIS;

 

   // Specific ADC setup for this example:

   AdcRegs.ADCTRL1.bit.CPS = 0; //ADCCLK = Prescaled HSPCLK (ADCCLKPS[3:0])

   AdcRegs.ADCTRL1.bit.ACQ_PS = 0; // ADC module clock = HSPCLK/1 = 25MHz

                             // If Simultaneous mode enabled: Sample rate = 1/[(3+ACQ_PS)*ADC clock in ns]

   AdcRegs.ADCTRL1.bit.SEQ_CASC = 1;       // Setup cascaded sequencer mode

   AdcRegs.ADCTRL1.bit.CONT_RUN = 1;       // Setup continuous run

   AdcRegs.ADCTRL1.bit.SEQ_OVRD = 1;       // Enable Sequencer override feature

 

   //AdcRegs.ADCTRL2.bit.RST_SEQ1 =  0x1;   //Immediately reset sequencer to state CONV00

   AdcRegs.ADCTRL2.bit.INT_ENA_SEQ1 = 0x1;//SEQ1 interrupt enable

   AdcRegs.ADCTRL2.bit.INT_MOD_SEQ1 = 0x0;//SEQ1 interrupt mode

 

   AdcRegs.ADCTRL3.bit.ADCCLKPS = 0x0;//HSPCLK

   AdcRegs.ADCTRL3.bit.SMODE_SEL = 0x1; // Setup simultaneous sampling mode

   AdcRegs.ADCTRL3.bit.ADCBGRFDN = 0x3; //The bandgap and reference circuitry is powered up.

   DELAY_US(1);

   AdcRegs.ADCTRL3.bit.ADCPWDN = 0x1;  //The analog circuitry inside the core is powered up

 

   AdcRegs.ADCMAXCONV.bit.MAX_CONV1 = 0x0; // 1 double conv's (2 total)

   AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x0;  // Setup conv from ADCINA0 &amp; ADCINB0

 

    DELAY_US(ADC_usDELAY);         // Delay before converting ADC channels

}

tao yang20：

回复 tao yang20:

我就搞不明了，咱用户这么诚心地来问问题，准备这么多材料，思考了那么长时间，为什么你们就不能多花一点时间来用同样的诚意解答呢，我看了论坛里也有很多这样类似的帖子，大部分都是三言两语的解答，我觉得这不能说明咱技术支持水平有多高，只能反映服务做得不够细，我之前经常在LinkedIn上直接问国外的大神，人家那严禁的态度真的让人佩服。

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