不韋 呂
/
UIT2_FIR_LPF_Symmetry
FIR filter of symmetric coefficiemts for ST Nucleo F401RE.
Diff: main.cpp
- Revision:
- 0:4912234b4155
- Child:
- 1:93d2771b8797
diff -r 000000000000 -r 4912234b4155 main.cpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Tue Oct 21 08:41:14 2014 +0000 @@ -0,0 +1,44 @@ +//-------------------------------------------------------------- +// FIR フィルタ,係数の対称性を利用する構造 +// Analog Input : A0 +// Analog Output: MCP4922 using SPI +// 2014/10/21, Copyright (c) 2014 MIKAMI, Naoki +//-------------------------------------------------------------- + +#include "mbed.h" + +#include "ADC_Interrupt.hpp" // for ADC using interrupt +#include "DAC_MCP4922.hpp" // for DAC MCP4922 +#include "ScfClockTim3.hpp" // for clock supplied to SCF +#include "Coefficients_200_LPF_Sym.hpp" + +using namespace Mikami; + +const int FS_ = 12000; // Sampling frequency: 12 kHz +ADC_Base adc_(A0, FS_); // for AD +DAC_MCP4922 myDac_(DAC_MCP4922::DAC_A); // for DA + +int main() +{ + ScfClockTim3(500000); // cutoff frequency: 5 kHz + + float xn[ORDER_+1]; + for (int n=0; n<=ORDER_; n++) + xn[n] = 0; + + while (true) + { + xn[0] = adc_.Read(); // Read from A0 + //----------------------------------------------- + + float yn = hm_[ORDER_/2]*xn[ORDER_/2]; + for (int k=0; k<ORDER_/2; k++) + yn = yn + hm_[k]*(xn[k] + xn[ORDER_-k]); + + for (int k=ORDER_; k>0; k--) + xn[k] = xn[k-1]; // move input signals + + //----------------------------------------------- + myDac_.Write(yn); // Write to DAC + } +}