fft (incomplete)

main.c

@@ -31,18 +31,32 @@
 #include "driverlib/pin_map.h"
 #include "sampling.h"
 #include "buttons.h"
+#include "kiss_fft.h"
+#include "_kiss_fft_guts.h"
+
 #define PWM_FREQUENCY 20000 // PWM frequency = 20 kHz
 
 uint32_t gSystemClock = 120000000; // [Hz] system clock frequency
 
+#define PI 3.14159265358979f
+
 tContext sContext;
 
 uint32_t cputime_unloaded;
 
+#define FFT_EN false
+
 #define LOCAL_BUF_LEN 128
 uint16_t adc_buffer_sample[LOCAL_BUF_LEN]; // copy of g adc buffer
 uint8_t adc_buffer_processed[LOCAL_BUF_LEN]; // copy of g adc buffer
 
+#define FFT_BUF_LEN 1024
+uint16_t adc_buffer_fft_sample[FFT_BUF_LEN]; // copy of g adc buffer
+uint8_t adc_buffer_fft_processed[FFT_BUF_LEN]; // copy of g adc buffer
+
+kiss_fft_cfg cfg;
+static kiss_fft_cpx in[FFT_BUF_LEN], out[FFT_BUF_LEN];
+
 typedef struct
 {
     uint8_t voltage_scale;
@@ -151,64 +165,94 @@ int main(void)
     GrContextInit(&sContext, &g_sCrystalfontz128x128); // Initialize the grlib graphics context
     GrContextFontSet(&sContext, &g_sFontFixed6x8); // select font
 
+    #define KISS_FFT_CFG_SIZE (sizeof(struct kiss_fft_state)+sizeof(kiss_fft_cpx)*(FFT_BUF_LEN-1))
+    static char kiss_fft_cfg_buffer[KISS_FFT_CFG_SIZE];
+    size_t buffer_size = KISS_FFT_CFG_SIZE;
+    cfg = kiss_fft_alloc(FFT_BUF_LEN, 0, kiss_fft_cfg_buffer, &buffer_size);
+
     /* Start BIOS */
     BIOS_start();
 
     return (0);
 }
 
-void task0_func(UArg arg1, UArg arg2)
-{
-    IntMasterEnable();
-
-    while (true) {
-        // do nothing
-    }
-}
-
 void capture_waveform(UArg arg1, UArg arg2)
 {
     IntMasterEnable();
     while(true) {
         Semaphore_pend(capture_sem, BIOS_WAIT_FOREVER);
 
-        // single read of options is atomic
-        int32_t trigger_mode = options.trigger_mode;
-
         int32_t adc_current_index;
-        int32_t j;
+        int32_t i;
-        int trigger;
+
-        if (trigger_mode == 2) {
+        if (true) {
-            trigger = gADCBufferIndex - (WIDTH / 2); // show latest if trigger disabled
+            adc_current_index = gADCBufferIndex;
+            for(i=adc_current_index-FFT_BUF_LEN; i<adc_current_index; i++) {
+                //in[i].r = sinf(20*PI*i/FFT_BUF_LEN);
+                in[i].r = (float) gADCBuffer[ADC_BUFFER_WRAP(adc_current_index + i)];
+                in[i].i = 0;
+            }
         } else {
-            trigger = Trigger(trigger_mode);
+            // single read of options is atomic
-        }
+            int32_t trigger_mode = options.trigger_mode;
 
-        adc_current_index = trigger - (WIDTH / 2);
+            int trigger;
-        for (j=0; j<LOCAL_BUF_LEN; j++) {
+            if (trigger_mode == 2) {
-            adc_buffer_sample[j] = gADCBuffer[ADC_BUFFER_WRAP(adc_current_index + j)];
+                trigger = gADCBufferIndex - (WIDTH / 2); // show latest if trigger disabled
-        }
+            } else {
+                trigger = Trigger(trigger_mode);
+            }
 
+            adc_current_index = trigger - (WIDTH / 2);
+            for (i=0; i<LOCAL_BUF_LEN; i++) {
+                adc_buffer_sample[i] = gADCBuffer[ADC_BUFFER_WRAP(adc_current_index + i)];
+            }
+
+        }
         Semaphore_post(process_sem);
     }
 }
 
 void process_waveform(UArg arg1, UArg arg2) {
+    static float w[FFT_BUF_LEN];
+    int i;
+    for (i=0; i<FFT_BUF_LEN; i++) {
+        w[i] = 0.42f
+            - 0.5f * cosf(2*PI*i/(FFT_BUF_LEN-1))
+            + 0.08f * cosf(4*PI*i/(FFT_BUF_LEN-1));
+    }
     while(true) {
         Semaphore_pend(process_sem, BIOS_WAIT_FOREVER);
+        int i;
 
-        // single read of global options is atomic
+        #define MIN(a,b) (((a)<(b))?(a):(b))
+        #define MAX(a,b) (((a)>(b))?(a):(b))
+        #define CONSTRAIN(x) MAX(MIN(HEIGHT - 1, x), 0)
 
-        float fVoltsPerDiv = gVoltageScale[options.voltage_scale];
+        if(true) { // fft
-        float fScale = (VIN_RANGE * PIXELS_PER_DIV)/((1 << ADC_BITS) * fVoltsPerDiv);
+            for(i=0; i<FFT_BUF_LEN; i++) {
+                in[i].r *= w[i];
+            }
 
-        int j;
+            kiss_fft(cfg, in, out);
-        for(j=0; j<LOCAL_BUF_LEN; j++) {
+
-            #define MIN(a,b) (((a)<(b))?(a):(b))
+            for(i=0; i<LOCAL_BUF_LEN; i++) {
-            #define MAX(a,b) (((a)>(b))?(a):(b))
+                #define DB(out) 10 * log10f(out.r * out.r + out.i * out.i)
-            #define CONSTRAIN(x) MAX(MIN(HEIGHT - 1, x), 0)
+
-            #define TRANSPOSE(x) CONSTRAIN((HEIGHT/2) - (int)roundf(fScale * ((int)x - ADC_OFFSET)))
+                //adc_buffer_processed[i] = CONSTRAIN(HEIGHT- (int)roundf(0.5 * DB(out[i])));
-            adc_buffer_processed[j] = TRANSPOSE(adc_buffer_sample[j]);
+                adc_buffer_processed[i] = CONSTRAIN(HEIGHT- (int) (DB(out[i])) + 64);
+
+            }
+
+        } else {
+            // single read of global options is atomic
+            float fVoltsPerDiv = gVoltageScale[options.voltage_scale];
+            float fScale = (VIN_RANGE * PIXELS_PER_DIV)/((1 << ADC_BITS) * fVoltsPerDiv);
+
+            for(i=0; i<LOCAL_BUF_LEN; i++) {
+                #define TRANSPOSE(x) CONSTRAIN((HEIGHT/2) - (int)roundf(fScale * ((int)x - ADC_OFFSET)))
+                adc_buffer_processed[i] = TRANSPOSE(adc_buffer_sample[i]);
+            }
         }
 
         Semaphore_post(display_sem);
@@ -305,25 +349,8 @@ void display_waveform(UArg arg1, UArg arg2)
         // display graph
         GrContextForegroundSet(&sContext, ClrYellow);
         int j;
-        for(j=0; j<LOCAL_BUF_LEN; j++) {
+        for(j=1; j<LOCAL_BUF_LEN; j++) {
-            #define MIN(a,b) (((a)<(b))?(a):(b))
+            GrLineDraw(&sContext, j-1, adc_buffer_processed[j-1], j, adc_buffer_processed[j]);
-            #define MAX(a,b) (((a)>(b))?(a):(b))
-            uint32_t upper,lower, current, last;
-
-            if (j==0) {
-                upper = adc_buffer_processed[j];
-                lower = upper;
-                last = upper;
-            } else {
-                current = adc_buffer_processed[j];
-
-                upper = MAX(current, last);
-                lower = MIN(current, last);
-
-                last = current;
-            }
-
-            GrLineDrawV(&sContext, j, lower, upper);
         }
 
         GrFlush(&sContext); // flush the frame buffer to the LCD

rtos.cfg

@@ -536,10 +536,6 @@ var driversConfig = xdc.useModule('ti.drivers.Config');
 driversConfig.libType = driversConfig.LibType_NonInstrumented;
 Clock.timerId = 0;
 TimestampProvider.useClockTimer = true;
-var task0Params = new Task.Params();
-task0Params.instance.name = "task0";
-task0Params.priority = 1;
-Program.global.task0 = Task.create("&task0_func", task0Params);
 var m3Hwi0Params = new m3Hwi.Params();
 m3Hwi0Params.instance.name = "m3Hwi0";
 m3Hwi0Params.priority = 0;