fft.rar_dsp FFT_fft_fft dsp

经过多天的调试，终于调通了，为了方便大家少走弯路，带来痛苦，提高效率，下面将我的感受和源程序

写出来，供大家学习！！希望大家共同交流！这个我已经运行了，通过了，大家做的时候先用 matlab 验

证一下 sin 的频率！然后看计算结果对不！

2005.04.7 号上午八点 40 程序纪录，这个程序运算完全正确，和前一个程序不同

之处在 sin 值得大小，由于 2812 时定点运算，sin 值得大小不能太小！否则计算

结果为零！2812 的 fft 的错误在于 fft.init1(),fft.init2()这两个函数没有这函数库里

面定义，而是该用 fft.init(&fft),而且由于是定点运算，输入的 sin 值不能太小，要

不然计算结果为零！

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

// Prototype statements for functions found within this file.

// Global variables used in this example:

Uint16 LoopCount;

Uint16 ConversionCount;

Uint16 fftflag=0;//FFT 转换启动标志:0 不启动；1:启动

Uint16 i;

long Voltage1[BUF_SIZE];

long Voltage2[BUF_SIZE];

long ipcb[BUF_SIZE];

RFFT32 fft=RFFT32_128P_DEFAULTS;

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();

// For this example, set HSPCLK to SYSCLKOUT / 6 (25Mhz assuming 150Mhz SYSCLKOUT)

EALLOW;

SysCtrlRegs.HISPCP.all = 0x3; // HSPCLK = SYSCLKOUT/6

// Disable CPU interrupts

DINT;

// Initialize the PIE control registers to their default state.

// The default state is all PIE interrupts disabled and flags

// 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();

// Interrupts that are used in this example are re-mapped to

// ISR functions found within this file.

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

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

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;

for(i=0;i<BUF_SIZE;I++)