From 0974087d7f2600f4700063f727515d14113c4068 Mon Sep 17 00:00:00 2001
From: c vw <dl1ycf@darc.de>
Date: Wed, 11 Dec 2019 19:11:09 +0100
Subject: [PATCH] fixed "TX heartbeat" problem in old_protocol

---
 old_protocol.c | 66 +++++++++++++++++++++++++++++++++++---------------
 1 file changed, 46 insertions(+), 20 deletions(-)

diff --git a/old_protocol.c b/old_protocol.c
index 188dfd5..4c05757 100644
--- a/old_protocol.c
+++ b/old_protocol.c
@@ -252,6 +252,11 @@ static unsigned char ep6_inbuffer[EP6_BUFFER_SIZE];
 static unsigned char usb_buffer_block = 0;
 #endif
 
+#define MICRINGLEN 2048
+float mic_ring_buffer[MICRINGLEN];
+int   mic_ring_read_pt=0;
+int   mic_ring_write_pt=0;
+
 void old_protocol_stop() {
   metis_start_stop(0);
 }
@@ -980,24 +985,43 @@ static void process_ozy_input_buffer(unsigned char  *buffer) {
 
       // TX without PURESIGNAL: receivers are shut down -- do nothing
 
+      //
+      // Process mic samples. Take them from buffer or from
+      // "local microphone" ring buffer
+      //
       mic_sample  = (short)(buffer[b++]<<8);
       mic_sample |= (short)(buffer[b++]&0xFF);
-      if(!transmitter->local_microphone) {
-        mic_samples++;
-        if(mic_samples>=mic_sample_divisor) { // reduce to 48000
+
+      mic_samples++;
+      if(mic_samples>=mic_sample_divisor) { // reduce to 48000
+        if (!transmitter->local_microphone) {
+          // take mic sample from SDR
           fsample = (float) mic_sample * 0.00003051;
-#ifdef FREEDV
-          if(active_receiver->freedv) {
-            add_freedv_mic_sample(transmitter,fsample);
+        } else {
+          // take mic sample from local mic buffer
+          if (mic_ring_read_pt == mic_ring_write_pt) {
+            // nothing in buffer: insert silence
+            fsample=0.0;
           } else {
-#endif
-            add_mic_sample(transmitter,fsample);
-#ifdef FREEDV
+            int newpt = mic_ring_read_pt+1;
+            if (newpt == MICRINGLEN) newpt=0;
+            fsample=mic_ring_buffer[mic_ring_read_pt];
+            // atomic update of read pointer
+            mic_ring_read_pt=newpt;
           }
+        }
+#ifdef FREEDV
+        if(active_receiver->freedv) {
+          add_freedv_mic_sample(transmitter,fsample);
+        } else {
 #endif
-          mic_samples=0;
+          add_mic_sample(transmitter,fsample);
+#ifdef FREEDV
         }
+#endif
+        mic_samples=0;
       }
+
     }
   } else {
     time_t t;
@@ -1072,17 +1096,19 @@ void old_protocol_iq_samples(int isample,int qsample) {
   }
 }
 
-
+//
+// This function now simply puts the mic sample
+// into a ring buffer
+//
 void old_protocol_process_local_mic(float sample) {
-#ifdef FREEDV
-  if(active_receiver->freedv) {
-    add_freedv_mic_sample(transmitter,sample);
-  } else {
-#endif
-    add_mic_sample(transmitter,sample);
-#ifdef FREEDV
-  }
-#endif
+    int newpt;  // value of write pointer after a successful write
+    newpt=mic_ring_write_pt +1;
+    if (newpt == MICRINGLEN) newpt=0;
+    if (newpt != mic_ring_read_pt) {
+      // buffer space available, do the write
+      mic_ring_buffer[mic_ring_write_pt]=sample;
+      mic_ring_write_pt=newpt;
+    }
 }
 
 /*
-- 
2.45.2