example_281xadcseqmodetest.c

tms320f2812例子程序

//###########################################################################
//
// FILE:   Example_281xAdcSeqModeTest.c
//
// TITLE:  DSP281x ADC Seq Mode Test.
//
// ASSUMPTIONS:
//
//          This program requires the DSP281x V1.00 header files.  
//          As supplied, this project is configured for "boot to H0" operation.  
// 
//          Make sure the CPU clock speed is properly defined in 
//          DSP281x_Examples.h before compiling this example.
//
//          Connect the signal to be converted to channel A0.
//
// DESCRIPTION:    
//
//          Channel A0 is converted forever and logged in a buffer (SampleTable)
//
//          Open a memory window to SampleTable to observe the buffer
//          RUN for a while and stop and see the table contents.
//
//          Watch Variables:
//             SampleTable - Log of converted values.
//
//###########################################################################
//
// Original source by: S.S.
//
//  Ver | dd mmm yyyy | Who  | Description of changes
// =====|=============|======|===============================================
//  1.00| 11 Sep 2003 | L.H. | Updated for DSP281x Release - First Release
//###########################################################################

#include "DSP281x_Device.h"     // DSP281x Headerfile Include File
#include "DSP281x_Examples.h"   // DSP281x Examples Include File

// ADC start parameters
#define ADC_MODCLK 0x3   // HSPCLK = SYSCLKOUT/2*ADC_MODCLK2 = 150/(2*3)         = 25MHz
#define ADC_CKPS   0x1   // ADC module clock = HSPCLK/2*ADC_CKPS   = 25MHz/(1*2) = 12.5MHz
#define ADC_SHCLK  0xf   // S/H width in ADC module periods                      = 16 ADC clocks
#define AVG        1000  // Average sample limit
#define ZOFFSET    0x00  // Average Zero offset
#define BUF_SIZE   2048  // Sample buffer size

// Global variable for this example
Uint16 SampleTable[BUF_SIZE];

main() 
{
   Uint16 i;

// Step 1. Initialize System Control:
// PLL, WatchDog, enable Peripheral Clocks
// This example function is found in the DSP281x_SysCtrl.c file.
   InitSysCtrl();
      
// Specific clock setting for this example:      
   EALLOW;
   SysCtrlRegs.HISPCP.all = ADC_MODCLK;	// HSPCLK = SYSCLKOUT/ADC_MODCLK
   EDIS;

// Step 2. Initialize GPIO: 
// This example function is found in the DSP281x_Gpio.c file and
// illustrates how to set the GPIO to it's default state.
// InitGpio();  // Skipped for this example  

// Step 3. Clear all interrupts and initialize PIE vector table:
// Disable CPU interrupts 
   DINT;

// Initialize the PIE control registers to their default state.
// The default state is all PIE interrupts disabled and flags
// are cleared.  
// This function is found in the DSP281x_PieCtrl.c file.
   InitPieCtrl();

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

// Initialize the PIE vector table with pointers to the shell Interrupt 
// Service Routines (ISR).  
// This will populate the entire table, even if the interrupt
// is not used in this example.  This is useful for debug purposes.
// The shell ISR routines are found in DSP281x_DefaultIsr.c.
// This function is found in DSP281x_PieVect.c.
   InitPieVectTable();

// Step 4. Initialize all the Device Peripherals:
// This function is found in DSP281x_InitPeripherals.c
// InitPeripherals(); // Not required for this example
   InitAdc();  // For this example, init the ADC

// Specific ADC setup for this example:
   AdcRegs.ADCTRL1.bit.ACQ_PS = ADC_SHCLK;
   AdcRegs.ADCTRL3.bit.ADCCLKPS = ADC_CKPS;     
   AdcRegs.ADCTRL1.bit.SEQ_CASC = 1;        // 1  Cascaded mode
   AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x0;
   AdcRegs.ADCTRL1.bit.CONT_RUN = 1;       // Setup continuous run


// Step 5. User specific code, enable interrupts:


// Clear SampleTable
   for (i=0; i<BUF_SIZE; i++)
   {
     SampleTable[i] = 0;
   }

   // Start SEQ1
   AdcRegs.ADCTRL2.all = 0x2000;

   // Take ADC data and log the in SampleTable array  
   while(1)
   {  
     for (i=0; i<AVG; i++)
     {
        while (AdcRegs.ADCST.bit.INT_SEQ1== 0) {} // Wait for interrupt
        // Software wait = (HISPCP*2) * (ADCCLKPS*2) * (CPS+1) cycles
        //               = (3*2)      * (1*2)        * (0+1)   = 12 cycles
        asm(" RPT #11 || NOP");
        AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;
        SampleTable[i] =((AdcRegs.ADCRESULT0>>4) ); 
     }
   }
}

//===========================================================================
// No more.
//===========================================================================