Diff: filters.h

Revision:

4:59319802012b

Parent:

3:48258b86e182

Child:

5:ec6f2323a263

--- a/filters.h	Mon Feb 19 11:50:39 2018 +0000
+++ b/filters.h	Mon Feb 19 15:14:44 2018 +0000
@@ -9,35 +9,54 @@
 //    filter variables:      //
 ///////////////////////////////
 
-float SOSMatHP[2][6] = { // 25khz cutoff at 920 kHz sample rate // closer to 30kHz when io toggle switched off.
-    1.000000,  -2.000000,  1.000000,  1.000000,  -1.706510,  0.731145,
-    1.000000,  -2.000000,  1.000000,  1.000000,  -1.852377,  0.879117
-};
-float GscaleHP = 0.801724;
+// filter coeficients, best performance to declare in function (constant values).
+//float SOSMatHP[2][6] = { // 25khz cutoff at 920 kHz sample rate  // 50kHz cutoff at 1.4 Mhz sample rate
+//    1.000000,  -2.000000,  1.000000,  1.000000,  -1.706510,  0.731145,
+//    1.000000,  -2.000000,  1.000000,  1.000000,  -1.852377,  0.879117
+//};
+//float GscaleHP = 0.801724;
+//
+//// num sections
+//int NumSectionsHP = sizeof(SOSMatHP)/sizeof(float)/6;
 
 // second-order sections filter variables - upto 8 sections
 #define MAX_SECTION_NUMBER 8
-int NumSectionsHP = sizeof(SOSMatHP)/sizeof(float)/6;
 
 // convertions
-float ADC2Float=(2.0f/4095.0f); //ADCvalue*(2/0xFFF)-1.0f // 12 bits range
-float Float2ADC=(4095.0f/2.0f); //(ADCvalue+1.0f)*(0xFFF/2) // 12 bits range
+#define ADC2Float (2.0f/4095.0f) // 0.0004884f//
+#define Float2ADC (4095.0f/2.0f) // 2047.5f   //
+//float ADC2Float=(2.0f/4095.0f); //ADCvalue*(2/0xFFF)-1.0f // 12 bits range
+//float Float2ADC=(4095.0f/2.0f); //(ADCvalue+1.0f)*(0xFFF/2) // 12 bits range
 
 ///////////////////////////////
 //    available filters:     //
 ///////////////////////////////
-// no filter function (output equals input)
-inline void no_filter(void);
-// high pass filter
-inline void highpass_filter(void);
+// off mode, output vdd/2
+inline void offMode(void);
+// passthrough function (output equals input)
+inline void passthrough(void);
+// highpass filter
+inline void highpass(void);
+// highpass filter + trigger mode
+inline void highpassTrig(void);
 
 
 
 ///////////////////////////////
 //    Filter Functions:      //
 ///////////////////////////////
-// no filter function (output equals input)
-inline void no_filter(void)
+
+// off mode, output vdd/2
+inline void offMode(void){
+    uint16_t ADCValueOut;
+    // set to vdd/2
+    ADCValueOut=(uint16_t)((0.0f +1.0f) * Float2ADC);
+    // Output value using DAC
+    *(__IO uint32_t *) Dac_Reg  = ADCValueOut; 
+}// end off mode
+
+// passthrough function (output equals input)
+inline void passthrough(void)
 {
     uint32_t ADCValue;
 
@@ -46,12 +65,25 @@
     // Output value using DAC
     *(__IO uint32_t *) Dac_Reg  = ADCValue;
 
-} // end no filter
+} // end passthrough
 
 
 // high pass filter
-inline void highpass_filter(void)
+inline void highpass(void)
 {
+    ///////////////////////////////
+    //    filter variables:      //
+    ///////////////////////////////
+    // filter coeficients best performance if defined in loop
+    float SOSMatHP[2][6] = { // 25khz cutoff at 920 kHz sample rate // closer to 30kHz when io toggle switched off.
+        1.000000,  -2.000000,  1.000000,  1.000000,  -1.706510,  0.731145,
+        1.000000,  -2.000000,  1.000000,  1.000000,  -1.852377,  0.879117
+    };
+    float GscaleHP = 0.801724;
+
+    // num sections
+    int NumSectionsHP = sizeof(SOSMatHP)/sizeof(float)/6;
+
     float ADCFloat;
     float ADCFloatFiltered;
     uint16_t ADCValueOut;
@@ -60,7 +92,10 @@
     static float CurrInput [MAX_SECTION_NUMBER+1];
     static float LastInput [MAX_SECTION_NUMBER+1];
     static float LLastInput [MAX_SECTION_NUMBER+1];
-    // Read ADC input
+    
+    ////////////////////
+    // Read ADC input //
+    ////////////////////
     ADCFloat=((uint16_t)(hadc1.Instance->DR) * ADC2Float)-1.0f;
 
     //////////////////////////////////////////////////////
@@ -96,6 +131,70 @@
     // Output value using DAC
     // HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, ADCValueOut);
     *(__IO uint32_t *) Dac_Reg = ADCValueOut;
-    //wait_us(1);
+
+} // end high pass filter
+
+// highpass filter + trigger mode
+inline void highpassTrig(void){
+    ///////////////////////////////
+    //    filter variables:      //
+    ///////////////////////////////
+    // filter coeficients best performance if defined in loop
+    float SOSMatHP[2][6] = { // 25khz cutoff at 920 kHz sample rate // closer to 30kHz when io toggle switched off.
+        1.000000,  -2.000000,  1.000000,  1.000000,  -1.706510,  0.731145,
+        1.000000,  -2.000000,  1.000000,  1.000000,  -1.852377,  0.879117
+    };
+    float GscaleHP = 0.801724;
+
+    // num sections
+    int NumSectionsHP = sizeof(SOSMatHP)/sizeof(float)/6;
+
+    float ADCFloat;
+    float ADCFloatFiltered;
+    uint16_t ADCValueOut;
+
+    // filter stages variables
+    static float CurrInput [MAX_SECTION_NUMBER+1];
+    static float LastInput [MAX_SECTION_NUMBER+1];
+    static float LLastInput [MAX_SECTION_NUMBER+1];
+    
+    ////////////////////
+    // Read ADC input //
+    ////////////////////
+    ADCFloat=((uint16_t)(hadc1.Instance->DR) * ADC2Float)-1.0f;
 
-}
\ No newline at end of file
+    //////////////////////////////////////////////////////
+    // Apply Filter to input                            //
+    //////////////////////////////////////////////////////
+
+    LLastInput[0] = LastInput[0];
+    LastInput[0] = CurrInput[0];
+    CurrInput[0] = ADCFloat;
+    for (int ii=1; ii <= NumSectionsHP; ii++) {
+        LLastInput[ii] = LastInput[ii];
+        LastInput[ii] = CurrInput[ii];
+        CurrInput[ii] = SOSMatHP[ii-1][0]*CurrInput[ii-1] + SOSMatHP[ii-1][1]*LastInput[ii-1] +
+                        SOSMatHP[ii-1][2]*LLastInput[ii-1] -
+                        SOSMatHP[ii-1][4]*LastInput[ii] - SOSMatHP[ii-1][5]*LLastInput[ii];
+        ADCFloatFiltered = CurrInput[ii];
+    }
+
+    ADCFloatFiltered = ADCFloatFiltered * GscaleHP;
+
+    ////////////////////////////
+    // Apply Filter to Output //
+    ////////////////////////////
+
+    if (ADCFloatFiltered < -1.0f) {
+        ADCValueOut=0; // Min value
+    } else if (ADCFloatFiltered > 1.0f) {
+        ADCValueOut=0xFFF; // Max value
+    } else {
+        ADCValueOut=(uint16_t)((ADCFloatFiltered +1.0f) * Float2ADC);
+    }
+
+    // Output value using DAC
+    // HAL_DAC_SetValue(&hdac1, DAC_CHANNEL_1, DAC_ALIGN_12B_R, ADCValueOut);
+    *(__IO uint32_t *) Dac_Reg = ADCValueOut/2;
+    //wait_us(1);
+} // end high pass filter + trigger mode
\ No newline at end of file