Audio: first draft

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

@@ -0,0 +1,104 @@
+
+#include "Audio.h"
+
+static void TC_SetRA(Tc *tc, uint32_t chan, uint32_t v) {
+	tc->TC_CHANNEL[chan].TC_RA = v;
+}
+
+static void TC_SetRB(Tc *tc, uint32_t chan, uint32_t v) {
+	tc->TC_CHANNEL[chan].TC_RB = v;
+}
+
+static void TC_SetRC(Tc *tc, uint32_t chan, uint32_t v) {
+	tc->TC_CHANNEL[chan].TC_RC = v;
+}
+
+void AudioClass::begin(uint32_t sampleRate) {
+	// Enable clock for DAC
+	pmc_enable_periph_clk(dacId);
+
+	dacc_reset(dac);
+
+	// Set transfer mode to double word
+	dacc_set_transfer_mode(dac, 1);
+
+	// Power save:
+	// sleep mode  - 0 (disabled)
+	// fast wakeup - 0 (disabled)
+	dacc_set_power_save(dac, 0, 0);
+
+	// ADC refresh/startup timings:
+	// refresh        - 0x08 (1024*8 dacc clocks)
+	// max speed mode -    0 (disabled)
+	// startup time   - 0x10 (1024 dacc clocks)
+	dacc_set_timing(dac, 0x08, 0, DACC_MR_STARTUP_1024);
+
+	// Flexible channel selection with tags
+	dacc_enable_flexible_selection(dac);
+
+	// Set up analog current
+	dacc_set_analog_control(dac,
+			DACC_ACR_IBCTLCH0(0x02) |
+			DACC_ACR_IBCTLCH1(0x02) |
+			DACC_ACR_IBCTLDACCORE(0x01));
+
+	// Enable output channels
+	dacc_enable_channel(dac, 0);
+	dacc_enable_channel(dac, 1);
+
+
+	// Configure Timer Counter to trigger DAC
+	// --------------------------------------
+	pmc_enable_periph_clk(ID_TC0);
+	TC_Configure(TC0, 1,
+		TC_CMR_TCCLKS_TIMER_CLOCK2 |
+		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);
+	const uint32_t TC = VARIANT_MCK / 8 / sampleRate;
+	TC_SetRA(TC0, 1, TC / 2);
+	TC_SetRC(TC0, 1, TC);
+	TC_Start(TC0, 1);
+
+	// Configure clock source for DAC (1 = TC0 Output Chan. 1)
+	dacc_set_trigger(dac, 1);
+}
+
+void AudioClass::end() {
+	TC_Stop(TC0, 1);
+	dacc_disable_channel(dac, 0);
+	dacc_disable_channel(dac, 1);
+}
+
+size_t AudioClass::write(const uint8_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_TCR = size;
+		dac->DACC_PTCR = DACC_PTCR_TXTEN;
+		return size;
+	}
+
+	// Try the second PDC buffer
+	if (dac->DACC_TNCR == 0) {
+		dac->DACC_TNPR = (uint32_t) buffer;
+		dac->DACC_TNCR = size;
+		dac->DACC_PTCR = DACC_PTCR_TXTEN;
+		return size;
+	}
+
+	// PDC buffers full, try again later...
+	return 0;
+}
+
+AudioClass Audio(DACC_INTERFACE, DACC_INTERFACE_ID);
+
+//void DACC_IrqHandler(void) {
+//	uint32_t sr = DACC_INTERFACE->DACC_ISR;
+//
+//	if (sr & DACC_ISR_ENDTX) {
+//		/* End of transmission */
+//		Audio.write(wBuffer, SAMPLES);
+//	}
+//}

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

@@ -0,0 +1,24 @@
+#ifndef AUDIO_H
+#define AUDIO_H
+
+#include "Arduino.h"
+//#include <inttypes.h>
+#include "Print.h"
+
+class AudioClass : public Print {
+public:
+	AudioClass(Dacc *_dac, uint32_t _dacId) : dac(_dac), dacId(_dacId) { };
+	void begin(uint32_t sampleRate);
+	void end();
+
+	virtual size_t write(uint8_t c) { write(&c, 1); };
+	virtual size_t write(const uint8_t *buffer, size_t size);
+
+private:
+	Dacc *dac;
+	uint32_t dacId;
+};
+
+extern AudioClass Audio;
+
+#endif