toggle fft

cast in high priority task was causing data issues + buffer overflow causing crazy issues

main.c

@@ -59,12 +59,14 @@ static kiss_fft_cpx in[FFT_BUF_LEN], out[FFT_BUF_LEN];
 
 typedef struct
 {
+    bool fft;
     uint8_t voltage_scale;
     uint8_t time_scale;
     uint8_t trigger_mode;
 } Options;
 
 Options options = {
+   .fft = false, // oscilloscope mode
    .voltage_scale = 4, // 2v
    .time_scale = 5, // 20us
    .trigger_mode = 1, // rising
@@ -185,12 +187,11 @@ void capture_waveform(UArg arg1, UArg arg2)
         int32_t adc_current_index;
         int32_t i;
 
-        if (true) {
+        if (options.fft) {
             adc_current_index = gADCBufferIndex;
+            int32_t j = 0;
             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;
+                adc_buffer_fft_sample[j++] = gADCBuffer[ADC_BUFFER_WRAP(adc_current_index + i)];
             }
         } else {
             // single read of options is atomic
@@ -229,9 +230,11 @@ void process_waveform(UArg arg1, UArg arg2) {
         #define MAX(a,b) (((a)>(b))?(a):(b))
         #define CONSTRAIN(x) MAX(MIN(HEIGHT - 1, x), 0)
 
-        if(true) { // fft
+        if(options.fft) { // fft
             for(i=0; i<FFT_BUF_LEN; i++) {
-                in[i].r *= w[i];
+                //in[i].r = sinf(20*PI*i/FFT_BUF_LEN);
+                in[i].r = (float) adc_buffer_fft_sample[i] * w[i];
+                in[i].i = 0;
             }
 
             kiss_fft(cfg, in, out);
@@ -240,7 +243,7 @@ void process_waveform(UArg arg1, UArg arg2) {
                 #define DB(out) 10 * log10f(out.r * out.r + out.i * out.i)
 
                 //adc_buffer_processed[i] = CONSTRAIN(HEIGHT- (int)roundf(0.5 * DB(out[i])));
-                adc_buffer_processed[i] = CONSTRAIN(HEIGHT- (int) (DB(out[i])) + 64);
+                adc_buffer_processed[i] = CONSTRAIN(HEIGHT- (int) (DB(out[i])) );
 
             }
 
@@ -271,6 +274,9 @@ void handle_user_input() {
             case S1: // toggle edge
                 local_options.trigger_mode = (local_options.trigger_mode + 1) % 3;
                 break;
+            case S2: // toggle fft
+                local_options.fft ^= 1;
+                break;
             case Up: // next scale
                 local_options.voltage_scale = (local_options.voltage_scale + 1) % VOLTAGE_SCALES;
                 break;