Diff: main.cpp

Revision:

2:8ae58834937f

Parent:

1:4fe83f71b889

Child:

3:30dcfcf9412c

--- a/main.cpp	Wed Feb 05 02:49:00 2014 +0000
+++ b/main.cpp	Mon Mar 10 23:33:38 2014 +0000
@@ -1,13 +1,124 @@
 #include "mbed.h"
+#include "FIR_f32.h"
 #include "arm_math.h"
-#include "arm_fir_f32.c" //the full path is cmsis_dsp/FilteringFunctions/arm_fir_f32.c
+#define f_sampling 2000 //the sampling frequency
+#define NumTaps 27      //the number of FIR coefficients
+#define BlockSize 1024  //the size of the buffer
+
+Serial pc(USBTX, USBRX); //USB serial for PC, to be removed later
+AnalogIn input(p15); //pin 15 for analog reading
+float32_t waveform[BlockSize]; //array of input data
+float32_t postFilterData[BlockSize]; //array of filtered data
+bool fullRead; //whether the MBED has finish
+bool waitForNext;
+
+//the filter coefficients for a band pass filter, consider changing to doubles if not precise enough
+float32_t pCoeffs[NumTaps] = 
+                {    0.012000000000000,   0.012462263166161,  -0.019562318415964,  -0.026175892863747,
+                     0.031654803781611,   0.050648026372209,  -0.032547136829180,  -0.070997780956819,
+                     0.032992306874347,   0.094643188024724,  -0.020568171368385,  -0.106071176200193,
+                     0.009515198320277,   0.114090808482376,   0.009515198320275,  -0.106071176200193,
+                    -0.020568171368382,   0.094643188024728,   0.032992306874351,  -0.070997780956815,
+                    -0.032547136829177,   0.050648026372211,   0.031654803781612,  -0.026175892863746,
+                    -0.019562318415964,   0.012462263166161,   0.012000000000000                        };
+float32_t pState[NumTaps + BlockSize - 1];
+
+                    
+int index_g; //tracks the index for the waveform array
 
-DigitalOut myled(LED1);
+
+void readPoint()
+{
+    waitForNext = false;    
+}
+
+
+/**
+* This function reads one full set of analog data into the uC 
+*/
+void readSamples()
+{
+    Ticker sampler; //allows for precision data reading
+    waitForNext = true;
+    sampler.attach_us(&readPoint, (int) (1000000/f_sampling) ); //read in data according the sampling freq
+    for (int i = 0; i < BlockSize; i++)
+    {
+        while (waitForNext); //wait until the ticker calls for the next sample
+        waveform[i] = input.read();
+        waitForNext = true;
+    }
+    sampler.detach();
+}
+    
 
 int main() {
-    //to initialize the filter stuff use the kind of form below (see line 104 in the arm_fir_f32.c file for documentation)
-    //arm_fir_instance_f32 S = {numTaps, pState, pCoeffs};
+    //to initialize the filter stuff use init functions (see line 89 in the arm_fir_f32.c file for documentation)
+    //the initialization function is in a seperate file called arm_fir_init_f32.c 
+    
+    /*
+* <code>pState</code> points to a state array of size <code>numTaps + blockSize - 1</code>.  
+* Samples in the state buffer are stored in the following order.  
+* \par  
+* <pre>  
+*    {x[n-numTaps+1], x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2]....x[0], x[1], ..., x[blockSize-1]}  
+* </pre>  
+* \par  
+    
+    */
+    arm_fir_instance_f32* filter = new arm_fir_instance_f32();
+    int state = 0;
+    uint16_t numTaps = NumTaps;
+    uint32_t blockSize = BlockSize;
+    while(1) 
+    {
+        //pc.printf("While loop\n\r");
+        switch(state)
+        {
+        case 0: //initialization
 
-    while(1) {
-    }
+            //pc.printf("pre-filter init\n\r");
+            arm_fir_init_f32(filter, numTaps, pCoeffs, pState, blockSize);
+            //pc.printf("Pre-attachment");
+            
+            state = 1;
+            pc.printf("Done with init.\n\r");
+            break;
+            
+        case 1: //read data, take samples
+            pc.printf("Reading data.\n\r");
+            readSamples();
+            state = 2;
+            break;
+            
+        case 2: //printout to pc connection
+            //pc.printf("into print\n\r");
+            /*
+            for (int i = 0; i < BlockSize; i++)
+            {
+                pc.printf("Waveform contents:%f\n\r", waveform[i]);
+            }
+            */
+            state = 3;
+            break;
+        case 3: //filter?
+            pc.printf("Filtering?\n\r");
+            arm_fir_f32(filter, waveform, postFilterData, blockSize);
+            state = 6;
+            break;
+        case 4: //FFT?
+            break;
+        case 5: //output, write to display and PWM tone
+            break;
+        case 6: //calculate the average voltage
+            double sum = 0;
+            for (int i = 0; i < BlockSize; i++) sum += postFilterData[i];
+            double average = sum/BlockSize*3.3;  //*3.3 V_ref (array stored as fractions of V_ref)
+            pc.printf("Average = %f\n\r", average);
+            wait_ms(500);
+            state = 1;
+            break;
+        default:
+            break;
+        }
+    } //end of (infinite) while loop
 }