From b245be464f93e2d930ea544405d60796cf3fec6c Mon Sep 17 00:00:00 2001
From: Geoffrey Merck <F4FXL@users.noreply.github.com>
Date: Wed, 13 May 2020 22:57:42 +0200
Subject: [PATCH 1/2] Fix txbuffer overflows and bring back elegant while loop

---
 FM.cpp | 27 +++++----------------------
 1 file changed, 5 insertions(+), 22 deletions(-)

diff --git a/FM.cpp b/FM.cpp
index 6315f36..19e980f 100644
--- a/FM.cpp
+++ b/FM.cpp
@@ -20,7 +20,7 @@
 #include "Globals.h"
 #include "FM.h"
 
-const uint16_t FM_TX_BLOCK_SIZE = 400U;
+const uint16_t FM_TX_BLOCK_SIZE = 100U;
 const uint16_t FM_SERIAL_BLOCK_SIZE = 42U;//this is actually the number of sample pairs to send over serial. One sample pair is 3bytes.
                                           //three times this value shall never exceed 126 !
 
@@ -152,30 +152,13 @@ void CFM::samples(bool cos, q15_t* samples, uint8_t length)
 
 void CFM::process()
 {
-  uint16_t space = io.getSpace() - 2U;
-  uint16_t length = m_outputRFRB.getData();
-  if (space > 2 && length >= FM_TX_BLOCK_SIZE ) {
-    
-    if(length > FM_TX_BLOCK_SIZE)
-      length = FM_TX_BLOCK_SIZE;
-    if(space > FM_TX_BLOCK_SIZE)
-      space = FM_TX_BLOCK_SIZE;
-    if(length > space)
-      length = space;
-
-    q15_t samples[FM_TX_BLOCK_SIZE];
-
-    for (uint16_t i = 0U; i < length; i++) {
-      q15_t sample = 0;
-      m_outputRFRB.get(sample);
-      samples[i] = sample;
-    }
-
-    io.write(STATE_FM, samples, length);
+  q15_t sample;
+  while (io.getSpace() >= 3U && m_outputRFRB.get(sample)) {
+    io.write(STATE_FM, &sample, 1);
   }
 
   if(m_extEnabled) {
-    length = m_downsampler.getData();
+    uint16_t length = m_downsampler.getData();
 
     if(length >= FM_SERIAL_BLOCK_SIZE) {
       if(length > FM_SERIAL_BLOCK_SIZE)

From cfcb7ed8524b65f83048f49f56432efaec3bddd4 Mon Sep 17 00:00:00 2001
From: Geoffrey Merck <F4FXL@users.noreply.github.com>
Date: Thu, 14 May 2020 09:10:11 +0200
Subject: [PATCH 2/2] Really fix TX Buffer ovrflows,, reduce delay buffer
 memory footprint

---
 FM.cpp | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/FM.cpp b/FM.cpp
index 19e980f..f4174fc 100644
--- a/FM.cpp
+++ b/FM.cpp
@@ -54,7 +54,7 @@ m_extAudioBoost(1U),
 m_downsampler(400U),// 100 ms of audio
 m_extEnabled(false),
 m_rxLevel(1),
-m_inputRFRB(4800U),   // 200ms of audio
+m_inputRFRB(2401U),   // 100ms of audio + 1 sample
 m_outputRFRB(2400U),  // 100ms of audio
 m_inputExtRB(2400U)   // 100ms of Audio
 {
@@ -152,9 +152,26 @@ void CFM::samples(bool cos, q15_t* samples, uint8_t length)
 
 void CFM::process()
 {
-  q15_t sample;
-  while (io.getSpace() >= 3U && m_outputRFRB.get(sample)) {
-    io.write(STATE_FM, &sample, 1);
+  uint16_t space = io.getSpace();
+  uint16_t length = m_outputRFRB.getData();
+  if (space > FM_TX_BLOCK_SIZE && length >= FM_TX_BLOCK_SIZE ) {
+    
+    if(length > FM_TX_BLOCK_SIZE)
+      length = FM_TX_BLOCK_SIZE;
+    if(space > FM_TX_BLOCK_SIZE)
+      space = FM_TX_BLOCK_SIZE;
+    if(length > space)
+      length = space;
+
+    q15_t samples[FM_TX_BLOCK_SIZE];
+
+    for (uint16_t i = 0U; i < length; i++) {
+      q15_t sample = 0;
+      m_outputRFRB.get(sample);
+      samples[i] = sample;
+    }
+
+    io.write(STATE_FM, samples, length);
   }
 
   if(m_extEnabled) {