From e136905e756afa92076cfcbfd019335608631679 Mon Sep 17 00:00:00 2001
From: Bertrand Songis <bsongis@gmail.com>
Date: Sat, 8 Aug 2015 00:12:39 +0200
Subject: [PATCH] Better fix for #2665

---
 radio/src/audio_arm.cpp                  |  5 ++++
 radio/src/targets/sky9x/audio_driver.cpp | 29 ++++++++++++++++++------
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/radio/src/audio_arm.cpp b/radio/src/audio_arm.cpp
index 721fe71d0..0d32f2a0f 100644
--- a/radio/src/audio_arm.cpp
+++ b/radio/src/audio_arm.cpp
@@ -475,7 +475,12 @@ const int16_t alawTable[256] = { -5504, -5248, -6016, -5760, -4480, -4224, -4992
 const int16_t ulawTable[256] = { -32124, -31100, -30076, -29052, -28028, -27004, -25980, -24956, -23932, -22908, -21884, -20860, -19836, -18812, -17788, -16764, -15996, -15484, -14972, -14460, -13948, -13436, -12924, -12412, -11900, -11388, -10876, -10364, -9852, -9340, -8828, -8316, -7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140, -5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092, -3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004, -2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980, -1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436, -1372, -1308, -1244, -1180, -1116, -1052, -988, -924, -876, -844, -812, -780, -748, -716, -684, -652, -620, -588, -556, -524, -492, -460, -428, -396, -372, -356, -340, -324, -308, -292, -276, -260, -244, -228, -212, -196, -180, -164, -148, -132, -120, -112, -104, -96, -88, -80, -72, -64, -56, -48, -40, -32, -24, -16, -8, 0, 32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956, 23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764, 15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412, 11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316, 7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140, 5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092, 3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004, 2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980, 1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436, 1372, 1308, 1244, 1180, 1116, 1052, 988, 924, 876, 844, 812, 780, 748, 716, 684, 652, 620, 588, 556, 524, 492, 460, 428, 396, 372, 356, 340, 324, 308, 292, 276, 260, 244, 228, 212, 196, 180, 164, 148, 132, 120, 112, 104, 96, 88, 80, 72, 64, 56, 48, 40, 32, 24, 16, 8, 0 };
 
 AudioQueue audioQueue;
+
+#if defined(PCBSKY9X)
+AudioBuffer audioBuffers[AUDIO_BUFFER_COUNT] __attribute__((aligned(32)));
+#else
 AudioBuffer audioBuffers[AUDIO_BUFFER_COUNT] _NOCCM;
+#endif
 
 AudioQueue::AudioQueue()
 {
diff --git a/radio/src/targets/sky9x/audio_driver.cpp b/radio/src/targets/sky9x/audio_driver.cpp
index 0a9c096a6..ed9f0ef9f 100644
--- a/radio/src/targets/sky9x/audio_driver.cpp
+++ b/radio/src/targets/sky9x/audio_driver.cpp
@@ -117,13 +117,28 @@ bool dacQueue(AudioBuffer *buffer)
 
 extern "C" void DAC_IRQHandler()
 {
-  AudioBuffer *nextBuffer = audioQueue.getNextFilledBuffer();
-  if (nextBuffer) {
-    DACC->DACC_TNPR = CONVERT_PTR_UINT(nextBuffer->data);
-    DACC->DACC_TNCR = nextBuffer->size/2;
-  }
-  else {
-    dacStop();
+  uint32_t sr = DACC->DACC_ISR;
+  if (sr & DACC_ISR_ENDTX) {
+    AudioBuffer *nextBuffer = audioQueue.getNextFilledBuffer();
+    if (nextBuffer) {
+	  // Try the first PDC buffer
+	  if ((DACC->DACC_TCR == 0) && (DACC->DACC_TNCR == 0)) {
+        DACC->DACC_TPR = CONVERT_PTR_UINT(nextBuffer->data);
+        DACC->DACC_TCR = nextBuffer->size/2;
+        DACC->DACC_PTCR = DACC_PTCR_TXTEN;
+        return;
+      }
+	  // Try the second PDC buffer
+      if (DACC->DACC_TNCR == 0) {
+        DACC->DACC_TNPR = CONVERT_PTR_UINT(nextBuffer->data);
+        DACC->DACC_TNCR = nextBuffer->size/2;
+        DACC->DACC_PTCR = DACC_PTCR_TXTEN;
+        return;
+      }
+    }
+    else {
+      dacStop();
+    }
   }
 }