Diff: main.cpp

Revision:

0:797a9c10261e

Child:

1:a2ca73edd772

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Oct 22 02:11:49 2014 +0000
@@ -0,0 +1,48 @@
+//--------------------------------------------------------------
+// FIR フィルタ，基本的な構造, 固定小数点演算用 DSP 命令を使う
+//      Analog Input : A0
+//      Analog Output: MCP4922 using SPI
+// 2014/10/21, Copyright (c) 2014 MIKAMI, Naoki
+//--------------------------------------------------------------
+
+#include "mbed.h"
+
+#include "ADC_Base.hpp"         // for ADC not using interrupt
+#include "DAC_MCP4922.hpp"      // for DAC MCP4922
+#include "ScfClockTim3.hpp"     // for clock supplied to SCF
+#include "Coefficients_200_LPF_Fixed.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
+
+    int16_t xn[ORDER_+1];
+    for (int n=0; n<=ORDER_; n++)
+        xn[n] = 0;
+    
+    while (true)
+    {
+        xn[0] = adc_.Read_u16() - 2047;     // Read from A0
+        //-----------------------------------------------
+
+        int32_t yn = hm_[ORDER_]*xn[ORDER_];;
+        for (int k=0; k<ORDER_; k+=2)
+        {
+            uint32_t x = __PKHBT(xn[k], xn[k+1], 16);
+            uint32_t h = __PKHBT(hm_[k], hm_[k+1], 16);
+            yn = __SMLAD(x, h, yn);     // Dual multiply and accumulate
+        }
+        for (int k=ORDER_; k>0; k--)
+            xn[k] = xn[k-1];        // move input signals
+
+        yn = (yn + 0x8000) >> 16;   // rounding and devide by 32768
+        //-----------------------------------------------
+        myDac_.Write((uint16_t)(yn + 2047));    // Write to DAC
+    }
+}