Working on audio out

code/radio/hilbert.c

@@ -0,0 +1,20 @@
+/*
+ * hilbert.c
+ *
+ *  Created on: Jul 9, 2020
+ *      Author: marshal
+ */
+
+#include <stdint.h>
+
+int16_t hilbert19(int16_t * src){
+  const size_t M = 19/2;
+  const int32_t coef[M/2+1];
+  int32_t sum;
+  sum  = (src[M-1]-src[M+1]) * coef[0];
+  sum += (src[M-3]-src[M+3]) * coef[1];
+  sum += (src[M-5]-src[M+5]) * coef[2];
+  sum += (src[M-7]-src[M+7]) * coef[3];
+  sum += (src[M-9]-src[M+9]) * coef[4];
+  return sum>>16;
+}

code/radio/rx.c

@@ -6,6 +6,7 @@
  */
 
 #include "rx.h"
+#include "ssb.h"
 
 /** Mailbox for received data */
 mailbox_t new_sample;
@@ -22,7 +23,11 @@ THD_FUNCTION(radio_rx, arg){
       data[i++] = c.real;
       data[i++] = c.imag;
     }
-    /** Here would be a good place to do a FFT or other processing */
+    /** Process the received data */
+    int16_t out[len];
+    ssb(out, data, len);
+    /** Fill buffer for audio out */
+    speaker_update(out, len);
   }
 }
 
@@ -111,3 +116,28 @@ void adc_rx_init(void){
   adcStartConversion(&ADCD1, &qsd_in, samples, len);
 
 }
+
+/** Copies audio data to PWM
+ *
+ */
+void speaker_callback(PWMDriver * pwmp){
+//FIXME: Copy data into DMA buffer. Or interrupt every period.
+}
+
+static PWMConfig spkr = {
+  4096000,                                    /* 4MHz PWM clock frequency.   */
+  4096,                                      /* Initial PWM period 1ms.       */
+  speaker_callback,
+  {
+   {PWM_OUTPUT_ACTIVE_HIGH, NULL},
+   {PWM_OUTPUT_DISABLED, NULL},
+   {PWM_OUTPUT_DISABLED, NULL},
+   {PWM_OUTPUT_DISABLED, NULL}
+  },
+  0,
+  0
+};
+
+void speaker_init(void){
+
+}

code/radio/rx.h

@@ -11,6 +11,19 @@
 #include "hal.h"
 #include "ch.h"
 
+/** Starts radio reception and demodulation
+ *
+ */
+void rxStart(uint8_t mode);
+
+/* Pauses radio reception and demodulation
+ *
+ */
+void rxStop(void);
+
+/** Handles the radio reception
+ *
+ */
 THD_FUNCTION(radio_rx, arg);
 
 /** Datatype for complex numbers
@@ -25,8 +38,28 @@ union complex{
   msg_t msg;
 };
 
+/** Radio RX thread
+ *
+ * This thread handles the data received from the ADC callback.
+ * It calls the specific radio protocol being run (CW, SSB, etc)
+ */
+THD_FUNCTION(radio_rx, arg);
+
+/** ADC streaming callback.
+ *
+ * Performs initial low-pass filter and downsamples to 5kHz
+ * Passes data to the Radio RX thread
+ */
+static void adccallback(ADCDriver *adcp);
+
 /** ADC init
+ *
+ * Configures the ADC for radio reception
  */
 void adc_rx_init(void);
 
+void speaker_init(void);
+
+void speaker_update(int16_t data, int len);
+
 #endif /* RX_H_ */

code/radio/ssb.c

@@ -0,0 +1,20 @@
+/*
+ * ssb.c
+ *
+ *  Created on: Jul 9, 2020
+ *      Author: marshal
+ */
+#include <stdint.h>
+#include "ssb.h"
+
+void ssb_rx(int16_t * dest, int16_t * src, size_t qty){
+  // Source data is interlieved In-phase / Quadrature phase
+  // Destination is single-channel
+  for(int i = 0; i < qty; ++i){
+    *dest++ = *src++ + *src++; // Return the sum of I and Q
+  }
+}
+
+void ssb_tx(int16_t * amp, int32_t * freq, int16_t * src, size_t qty){
+  // Source data is single-channel audio
+}

code/radio/ssb.h

@@ -0,0 +1,16 @@
+/*
+ * ssb.h
+ *
+ *  Created on: Jul 9, 2020
+ *      Author: marshal
+ */
+
+/** Single sideband decoder
+ *
+ */
+void ssb_rx(int16_t * dest, int16_t * src, size_t qty);
+
+/** Singgle sideband encoder
+ *
+ */
+void ssb_tx(int16_t * amp, int32_t * freq, int16_t * src, size_t qty);