Audio library: improved DMA transfers. Stereo output.

hardware/arduino/sam/libraries/Audio/Audio.cpp

@@ -1,3 +1,12 @@
+/*
+ * Copyright (c) 2012 by Cristian Maglie <c.maglie@bug.st>
+ * Audio library for Arduino Due.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either the GNU General Public License version 2
+ * or the GNU Lesser General Public License version 2.1, both as
+ * published by the Free Software Foundation.
+ */
 
 #include "Audio.h"
 
@@ -49,9 +58,9 @@ void AudioClass::begin(uint32_t sampleRate) {
 
 	// Configure Timer Counter to trigger DAC
 	// --------------------------------------
-	pmc_enable_periph_clk(ID_TC0);
+	pmc_enable_periph_clk(ID_TC1);
 	TC_Configure(TC0, 1,
-		TC_CMR_TCCLKS_TIMER_CLOCK2 |
+		TC_CMR_TCCLKS_TIMER_CLOCK2 |  // Clock at MCR/8
 		TC_CMR_WAVE |                 // Waveform mode
 		TC_CMR_WAVSEL_UP_RC |         // Counter running up and reset when equals to RC
 		TC_CMR_ACPA_SET | TC_CMR_ACPC_CLEAR);
@@ -60,8 +69,20 @@ void AudioClass::begin(uint32_t sampleRate) {
 	TC_SetRC(TC0, 1, TC);
 	TC_Start(TC0, 1);
 
-	// Configure clock source for DAC (1 = TC0 Output Chan. 1)
+	// Configure clock source for DAC (2 = TC0 Output Chan. 1)
-	dacc_set_trigger(dac, 1);
+	dacc_set_trigger(dac, 2);
+
+	// Configure pins
+	PIO_Configure(g_APinDescription[DA0].pPort,
+			g_APinDescription[DA0].ulPinType,
+			g_APinDescription[DA0].ulPin,
+			g_APinDescription[DA0].ulPinConfiguration);
+	PIO_Configure(g_APinDescription[DA1].pPort,
+			g_APinDescription[DA1].ulPinType,
+			g_APinDescription[DA1].ulPin,
+			g_APinDescription[DA1].ulPinConfiguration);
+
+	currentBuffer = 0;
 }
 
 void AudioClass::end() {
@@ -70,11 +91,10 @@ void AudioClass::end() {
 	dacc_disable_channel(dac, 1);
 }
 
-size_t AudioClass::write(const uint8_t *buffer, size_t size) {
+size_t AudioClass::write(const uint32_t *buffer, size_t size) {
-
 	// Try the first PDC buffer
 	if ((dac->DACC_TCR == 0) && (dac->DACC_TNCR == 0)) {
-		dac->DACC_TPR = (uint32_t) buffer;
+		dac->DACC_TPR = (uint32_t) cook(buffer, size);
 		dac->DACC_TCR = size;
 		dac->DACC_PTCR = DACC_PTCR_TXTEN;
 		return size;
@@ -82,7 +102,7 @@ size_t AudioClass::write(const uint8_t *buffer, size_t size) {
 
 	// Try the second PDC buffer
 	if (dac->DACC_TNCR == 0) {
-		dac->DACC_TNPR = (uint32_t) buffer;
+		dac->DACC_TNPR = (uint32_t) cook(buffer, size);
 		dac->DACC_TNCR = size;
 		dac->DACC_PTCR = DACC_PTCR_TXTEN;
 		return size;
@@ -92,6 +112,22 @@ size_t AudioClass::write(const uint8_t *buffer, size_t size) {
 	return 0;
 }
 
+uint32_t *AudioClass::cook(const uint32_t *buffer, size_t size) {
+	if (currentBuffer == 0) {
+		// Use buffer0
+		for (int i = 0; i < size; i++)
+			buffer0[i] = buffer[i] | 0x10000000;
+		currentBuffer = 1;
+		return buffer0;
+	} else {
+		// Use buffer1
+		for (int i = 0; i < size; i++)
+			buffer1[i] = buffer[i] | 0x10000000;
+		currentBuffer = 0;
+		return buffer1;
+	}
+}
+
 AudioClass Audio(DACC_INTERFACE, DACC_INTERFACE_ID);
 
 //void DACC_IrqHandler(void) {

hardware/arduino/sam/libraries/Audio/Audio.h

@@ -1,8 +1,17 @@
+/*
+ * Copyright (c) 2012 by Cristian Maglie <c.maglie@bug.st>
+ * Audio library for Arduino Due.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either the GNU General Public License version 2
+ * or the GNU Lesser General Public License version 2.1, both as
+ * published by the Free Software Foundation.
+ */
+
 #ifndef AUDIO_H
 #define AUDIO_H
 
 #include "Arduino.h"
-//#include <inttypes.h>
 #include "Print.h"
 
 class AudioClass : public Print {
@@ -11,10 +20,19 @@ public:
 	void begin(uint32_t sampleRate);
 	void end();
 
-	virtual size_t write(uint8_t c) { write(&c, 1); };
+	virtual size_t write(uint8_t c)                           { /* not implemented */ };
-	virtual size_t write(const uint8_t *buffer, size_t size);
+	virtual size_t write(const uint8_t *buffer, size_t size)  { return write((uint32_t*) buffer, size/4) * 4; };
+	virtual size_t write(const uint16_t *buffer, size_t size) { return write((uint32_t*) buffer, size/2) * 2; };
+	virtual size_t write(const int16_t *buffer, size_t size)  { return write((uint32_t*) buffer, size/2) * 2; };
+	virtual size_t write(const uint32_t *buffer, size_t size);
 
 private:
+	uint32_t buffer0[1024];
+	uint32_t buffer1[1024];
+	int currentBuffer;
+
+	uint32_t *cook(const uint32_t *buffer, size_t size);
+
 	Dacc *dac;
 	uint32_t dacId;
 };