买得研旭的板子,跟着手把手教学那本书在学,现在学到了ADC模块,根据研旭给的例程,对其中ADC模块产生中断的原理不懂,具体如下:(红 {MOD}为我标记不懂的地方,其他颜 {MOD}为例程程序)
#include "DSP2833x_Device.h" // DSP2833x Headerfile Include File
#include "DSP2833x_Examples.h" // DSP2833x Examples Include File
// Determine when the shift to right jus
tify the data takes place
// Only one of these should be defined as 1.
// The other two should be defined as 0.
#define POST_SHIFT 0 // Shift results after the entire sample table is full
#define INLINE_SHIFT 1 // Shift results as the data is taken from the results regsiter
#define NO_SHIFT 0 // Do not shift the results
// ADC start parameters
#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 ADC_CKPS 0x0 // ADC module clock = HSPCLK/1 = 25.5MHz/(1) = 25.0 MHz
#define ADC_SHCLK 0x1 // S/H width in ADC module periods = 2 ADC cycle
#define AVG 1000 // Average sample limit
#define ZOFFSET 0x00 // Average Zero offset
#define BUF_SIZE 512 // Sample buffer size
// Global variable for this example
Uint16 SampleTable[BUF_SIZE];
main()
{
Uint16 i;
Uint16 array_index=0;
InitSysCtrl();
EALLOW;
SysCtrlRegs.HISPCP.all = ADC_MODCLK; // HSPCLK = SYSCLKOUT/ADC_MODCLK
EDIS;
DINT;
InitPieCtrl();
// Disable CPU interrupts and clear all CPU interrupt flags:
IER = 0x0000;
IFR = 0x0000;
InitPieVectTable();
InitAdc(); // For this example, init the ADC
// Specific ADC setup for this example:
AdcRegs.ADCTRL1.bit.ACQ_PS = ADC_SHCLK; // Sequential mode: Sample rate = 1/[(2+ACQ_PS)*ADC clock in ns]
// = 1/(3*40ns) =8.3MHz (for 150 MHz SYSCLKOUT)
// = 1/(3*80ns) =4.17MHz (for 100 MHz SYSCLKOUT)
// If Simultaneous mode enabled: Sample rate = 1/[(3+ACQ_PS)*ADC clock in ns]
AdcRegs.ADCTRL3.bit.ADCCLKPS = ADC_CKPS;
AdcRegs.ADCTRL1.bit.SEQ_CASC = 1; // 1 Cascaded mode
AdcRegs.ADCCHSELSEQ1.bit.CONV00 = 0x1;
AdcRegs.ADCTRL1.bit.CONT_RUN = 1; // Setup continuous run
AdcRegs.ADCTRL1.bit.SEQ_OVRD = 1; // Enable Sequencer override feature
AdcRegs.ADCCHSELSEQ1.all = 0x0; // Initialize all ADC channel selects to A0
AdcRegs.ADCCHSELSEQ2.all = 0x0;
AdcRegs.ADCCHSELSEQ3.all = 0x0;
AdcRegs.ADCCHSELSEQ4.all = 0x0;
AdcRegs.ADCMAXCONV.bit.MAX_CONV1 = 0x1; // convert and store in 8 results registers
// Clear SampleTable
for (i=0; i<BUF_SIZE; i++)
{
SampleTable
= 0;
}
// Start SEQ1
AdcRegs.ADCTRL2.all = 0x2000;这么写值,并没有使能SEQ1或SEQ2的中断,难道是例程错了吗?
while(1)
{
// array_index = 0;
while(AdcRegs.ADCST.bit.INT_SEQ1 == 0);上面没有开中断,那么这里查询中断标志就没意义啊。
// GpioDataRegs.GPBSET.bit.GPIO34 = 1; // Set GPIO34 for monitoring -optional
AdcRegs.ADCST.bit.INT_SEQ1_CLR = 1;
SampleTable[array_index++]= ( (AdcRegs.ADCRESULT0)>>4);
if(array_index>(BUF_SIZE-1)) array_index=0;
DELAY_US(100);
GpioDataRegs.GPBCLEAR.bit.GPIO34 = 1; // Clear GPIO34 for monitoring -optional
}
}
//===========================================================================
// No more.
//===========================================================================
感谢各位解答!!
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