28335 - DSP实验报告(2)

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四、实验结果和分析

1、软件调试结果

图11 900Hz 1200mV正弦波调试结果 (上图)

图12 1700Hz 800mV正弦波调试结果 (上图)

图13 800Hz 1000mV三角波调试结果 (上图)

2、结果分析

(1)从图11所示的调试结果波形图可以看出，滤波后的波形平滑度明显变好，说明低

通滤波效果良好。各个波形参数MIN(最小值)、MAX(最大值)、VRM(有效值)、FRE(频率)、 PER(周期)均和实际输入的指标误差在

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5%以内，说明电参量的计算方法准确性良好。

(2)从图12所示的实验波形可以看出，当输入波形的电参量变化时，输出电参量的值也发生了相同变化，且误差值在5%以内。由ADC的采样频率可以得到，本程序可以计算出频率最低为150Hz的正弦波的周期。

(3)比较图13和前两幅波形可以得出，本程序在对三角波进行采样时，波形滤波效果良好，电参量计算准确，也达到了良好的效果。由此验证了本程序的通用性，并进一步验证了程序的准确性。

(4)通过实验结果总结出本程序在以下方面需要进一步改进：AD采样的速率以及采样窗口的大小目前为确定值，当波形频率变化范围较大时，会影响到采样的结果，如：当频率过大时，采样波形每个周期的点数减小，将直接影响各个电参量的计算结果；当频率过小时，采样的窗口不能采样出一个完整的波形周期，也将直接影响各个电参量的计算结果。这是需要进一步作出改进的地方。

五、源程序

#include \ // DSP2833x Headerfile Include File

#include File

\ // DSP2833x Examples Include #include \

// Prototype statements for functions found within this file. interrupt void adc_isr(void); interrupt void ISRTimer2(void); void number_count(void); 并发送数据 //确定周期采样点，计算频率和有效值void scib_fifo_init(); void InitScibGpio(void);

//串口初始化程序

void number_C(unsigned long i); //数字各位拆分函数

#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)

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

#define HSPCLK/2*ADC_CKPS ADC_CKPS = 25.0MHz/(1*2) = 12.5MHz

0x1 // ADC module clock = #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 160 // Sample buffer size

//Global variables used in this example: Uint16 LoopCount; Uint16 ConversionCount; Uint16 Voltage1[1024]; Uint16 i = 0; Uint16 j = 0; Uint16 Ticker[50];

//在AD采样的例程基础上修改，以下为新定义的变量： Uint16 ADt1,ADt2,ADt,ADt3,ADt4;//AD时间间隔 Uint16 Voltagelb[1024]; Uint16 vref=500; //参考值 int PreConversion=0; int crosszero=0;

Uint32 t1,t2,t,t3,t4;//定时器时间间隔 float Data=0.0; float Vavg=0.0;//平均值 float Vmax=0.0;//最大值

float Vmin=0.0;//最小值 float Vrms=0.0;//有效值 float Vpp=0.0;//峰峰值 float frequency=0; float period=0; float MAX=0.0; float MIN=0.0;

//以下为整型变量，用于串口发送 Uint16 T=0;//周期ms Uint16 F=0;//

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Uint16 V=0;//有效值mv Uint16 max=0;//最大值mv Uint16 min=0;//最小值mv unsigned int TX_flag = 0; //串口发送时间间隔标志 unsigned int TX_Ticker = 500; //串口发送的周期间隔 main() { // Step 1. Initialize System Control: // PLL, WatchDog, enable Peripheral Clocks // This example function is found in the DSP2833x_SysCtrl.c file. InitSysCtrl(); // Step 2. Initialize GPIO: // This example function is found in the DSP2833x_Gpio.c file and // illustrates how to set the GPIO to it's default state. InitGpio(); // Skipped for this example InitScibGpio();//*********************起初遗漏了这句话************************** // 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 DSP2833x_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 DSP2833x_DefaultIsr.c. // This function is found in DSP2833x_PieVect.c. InitPieVectTable(); // Interrupts that are used in this example are re-mapped to // ISR functions found within this file. EALLOW; // This is needed to write to EALLOW protected register PieVectTable.ADCINT = &adc_isr; PieVectTable.TINT2 = &ISRTimer2; EDIS; InitXintf(); /*设置CPU*/ InitCpuTimers(); ConfigCpuTimer(&CpuTimer2, 150, 10);//中断时间10us. 1MHz StartCpuTimer2(); CpuTimer2Regs.TCR.all = 0x4001; // Use write-only instruction to set TSS bit = 0 /*开中断*/ IER |= M_INT14; // Enable TINT0 in the PIE: Group 1 interrupt 7 PieCtrlRegs.PIEIER1.bit.INTx7 = 1; // Step 4. Initialize all the Device Peripherals: // This function is found in DSP2833x_InitPeripherals.c // InitPeripherals(); // Not required for this example InitAdc(); // For this example, init the ADC scib_fifo_init(); // Step 5. User specific code, enable interrupts: // Enable ADCINT in PIE PieCtrlRegs.PIEIER1.bit.INTx6 = 1; IER |= M_INT1; // Enable CPU Interrupt 1 EINT; // Enable Global interrupt INTM ERTM; // Enable Global realtime interrupt DBGM LoopCount = 0; ConversionCount = 0; AdcRegs.ADCTRL1.bit.ACQ_PS = ADC_SHCLK; AdcRegs.ADCTRL3.bit.ADCCLKPS = ADC_CKPS; AdcRegs.ADCTRL1.bit.SEQ_CASC = 1; …… 此处隐藏：5794字，全部文档内容请下载后查看。喜欢就下载吧 ……