Merge pull request #289 from FrankBoesing/master

SPDIF3, initial cache-support

Audio.h

 #include "output_pwm.h"
 #include "output_spdif.h"
 #include "output_spdif2.h"
+#include "output_spdif3.h"
 #include "output_pt8211.h"
 #include "output_pt8211_2.h"
 #include "output_tdm.h"

data_spdif.c

+/* Audio Library for Teensy 3.X
+ * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
+ *
+ * Development of this audio library was funded by PJRC.COM, LLC by sales of
+ * Teensy and Audio Adaptor boards.  Please support PJRC's efforts to develop
+ * open source software by purchasing Teensy or other PJRC products.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice, development funding notice, and this permission
+ * notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+ 
+#include <stdint.h>
+
+const __attribute__((aligned(32)))
+uint16_t spdif_bmclookup[256] = { //biphase mark encoded values (least significant bit first)
+	0xcccc, 0x4ccc, 0x2ccc, 0xaccc, 0x34cc, 0xb4cc, 0xd4cc, 0x54cc,
+	0x32cc, 0xb2cc, 0xd2cc, 0x52cc, 0xcacc, 0x4acc, 0x2acc, 0xaacc,
+	0x334c, 0xb34c, 0xd34c, 0x534c, 0xcb4c, 0x4b4c, 0x2b4c, 0xab4c,
+	0xcd4c, 0x4d4c, 0x2d4c, 0xad4c, 0x354c, 0xb54c, 0xd54c, 0x554c,
+	0x332c, 0xb32c, 0xd32c, 0x532c, 0xcb2c, 0x4b2c, 0x2b2c, 0xab2c,
+	0xcd2c, 0x4d2c, 0x2d2c, 0xad2c, 0x352c, 0xb52c, 0xd52c, 0x552c,
+	0xccac, 0x4cac, 0x2cac, 0xacac, 0x34ac, 0xb4ac, 0xd4ac, 0x54ac,
+	0x32ac, 0xb2ac, 0xd2ac, 0x52ac, 0xcaac, 0x4aac, 0x2aac, 0xaaac,
+	0x3334, 0xb334, 0xd334, 0x5334, 0xcb34, 0x4b34, 0x2b34, 0xab34,
+	0xcd34, 0x4d34, 0x2d34, 0xad34, 0x3534, 0xb534, 0xd534, 0x5534,
+	0xccb4, 0x4cb4, 0x2cb4, 0xacb4, 0x34b4, 0xb4b4, 0xd4b4, 0x54b4,
+	0x32b4, 0xb2b4, 0xd2b4, 0x52b4, 0xcab4, 0x4ab4, 0x2ab4, 0xaab4,
+	0xccd4, 0x4cd4, 0x2cd4, 0xacd4, 0x34d4, 0xb4d4, 0xd4d4, 0x54d4,
+	0x32d4, 0xb2d4, 0xd2d4, 0x52d4, 0xcad4, 0x4ad4, 0x2ad4, 0xaad4,
+	0x3354, 0xb354, 0xd354, 0x5354, 0xcb54, 0x4b54, 0x2b54, 0xab54,
+	0xcd54, 0x4d54, 0x2d54, 0xad54, 0x3554, 0xb554, 0xd554, 0x5554,
+	0x3332, 0xb332, 0xd332, 0x5332, 0xcb32, 0x4b32, 0x2b32, 0xab32,
+	0xcd32, 0x4d32, 0x2d32, 0xad32, 0x3532, 0xb532, 0xd532, 0x5532,
+	0xccb2, 0x4cb2, 0x2cb2, 0xacb2, 0x34b2, 0xb4b2, 0xd4b2, 0x54b2,
+	0x32b2, 0xb2b2, 0xd2b2, 0x52b2, 0xcab2, 0x4ab2, 0x2ab2, 0xaab2,
+	0xccd2, 0x4cd2, 0x2cd2, 0xacd2, 0x34d2, 0xb4d2, 0xd4d2, 0x54d2,
+	0x32d2, 0xb2d2, 0xd2d2, 0x52d2, 0xcad2, 0x4ad2, 0x2ad2, 0xaad2,
+	0x3352, 0xb352, 0xd352, 0x5352, 0xcb52, 0x4b52, 0x2b52, 0xab52,
+	0xcd52, 0x4d52, 0x2d52, 0xad52, 0x3552, 0xb552, 0xd552, 0x5552,
+	0xccca, 0x4cca, 0x2cca, 0xacca, 0x34ca, 0xb4ca, 0xd4ca, 0x54ca,
+	0x32ca, 0xb2ca, 0xd2ca, 0x52ca, 0xcaca, 0x4aca, 0x2aca, 0xaaca,
+	0x334a, 0xb34a, 0xd34a, 0x534a, 0xcb4a, 0x4b4a, 0x2b4a, 0xab4a,
+	0xcd4a, 0x4d4a, 0x2d4a, 0xad4a, 0x354a, 0xb54a, 0xd54a, 0x554a,
+	0x332a, 0xb32a, 0xd32a, 0x532a, 0xcb2a, 0x4b2a, 0x2b2a, 0xab2a,
+	0xcd2a, 0x4d2a, 0x2d2a, 0xad2a, 0x352a, 0xb52a, 0xd52a, 0x552a,
+	0xccaa, 0x4caa, 0x2caa, 0xacaa, 0x34aa, 0xb4aa, 0xd4aa, 0x54aa,
+	0x32aa, 0xb2aa, 0xd2aa, 0x52aa, 0xcaaa, 0x4aaa, 0x2aaa, 0xaaaa
+};

keywords.txt

 AudioOutputI2Sslave	KEYWORD2
 AudioOutputSPDIF	KEYWORD2
 AudioOutputSPDIF2	KEYWORD2
+AudioOutputSPDIF3	KEYWORD2
 AudioOutputPT8211	KEYWORD2
 AudioOutputPT8211_2	KEYWORD2
 AudioOutputTDM	KEYWORD2

output_i2s.cpp

 uint16_t  AudioOutputI2S::block_left_offset = 0;
 uint16_t  AudioOutputI2S::block_right_offset = 0;
 bool AudioOutputI2S::update_responsibility = false;
-static uint32_t i2s_tx_buffer[AUDIO_BLOCK_SAMPLES];
 DMAChannel AudioOutputI2S::dma(false);
+DMAMEM __attribute__((aligned(32))) static uint32_t i2s_tx_buffer[AUDIO_BLOCK_SAMPLES];
 
 #if defined(__IMXRT1052__) || defined(__IMXRT1062__)
 #include "utility/imxrt_hw.h"
 		offsetR += AUDIO_BLOCK_SAMPLES / 2;
 	} else {
 		memset(dest,0,AUDIO_BLOCK_SAMPLES * 2);
-		return;
 	}
 
+	#if IMXRT_CACHE_ENABLED >= 2		
+	arm_dcache_flush_delete(dest, sizeof(i2s_tx_buffer) / 2 );
+	#endif
+	
 	if (offsetL < AUDIO_BLOCK_SAMPLES) {
 		AudioOutputI2S::block_left_offset = offsetL;
 	} else {

output_i2s2.cpp

 uint16_t  AudioOutputI2S2::block_left_offset = 0;
 uint16_t  AudioOutputI2S2::block_right_offset = 0;
 bool AudioOutputI2S2::update_responsibility = false;
-static uint32_t i2s2_tx_buffer[AUDIO_BLOCK_SAMPLES];
 DMAChannel AudioOutputI2S2::dma(false);
-
+DMAMEM __attribute__((aligned(32))) static uint32_t i2s2_tx_buffer[AUDIO_BLOCK_SAMPLES];
 
 #include "utility/imxrt_hw.h"
 
 		memcpy_tointerleaveR(dest, blockR->data + offsetR);
 		offsetR += AUDIO_BLOCK_SAMPLES / 2;
 	} else {
-		memset(dest,0,AUDIO_BLOCK_SAMPLES * 2);
-		return;
+		memset(dest,0,AUDIO_BLOCK_SAMPLES * 2);		
 	}
 
+	#if IMXRT_CACHE_ENABLED >= 2		
+	arm_dcache_flush_delete(dest, sizeof(i2s2_tx_buffer) / 2 );
+	#endif	
+	
 	if (offsetL < AUDIO_BLOCK_SAMPLES) {
 		AudioOutputI2S2::block_left_offset = offsetL;
 	} else {

output_mqs.cpp

 uint16_t  AudioOutputMQS::block_left_offset = 0;
 uint16_t  AudioOutputMQS::block_right_offset = 0;
 bool AudioOutputMQS::update_responsibility = false;
-static uint32_t I2S3_tx_buffer[AUDIO_BLOCK_SAMPLES];
 DMAChannel AudioOutputMQS::dma(false);
+DMAMEM __attribute__((aligned(32)))
+static uint32_t I2S3_tx_buffer[AUDIO_BLOCK_SAMPLES];
+
 
 void AudioOutputMQS::begin(void)
 {
 	if (blockL && blockR) {
 		memcpy_tointerleaveLR(dest, blockL->data + offsetL, blockR->data + offsetR);
 		offsetL += AUDIO_BLOCK_SAMPLES / 2;
-		offsetR += AUDIO_BLOCK_SAMPLES / 2;
+		offsetR += AUDIO_BLOCK_SAMPLES / 2;	
 	} else if (blockL) {
 		memcpy_tointerleaveL(dest, blockL->data + offsetL);
-		offsetL += AUDIO_BLOCK_SAMPLES / 2;
+		offsetL += AUDIO_BLOCK_SAMPLES / 2;		
 	} else if (blockR) {
 		memcpy_tointerleaveR(dest, blockR->data + offsetR);
-		offsetR += AUDIO_BLOCK_SAMPLES / 2;
+		offsetR += AUDIO_BLOCK_SAMPLES / 2;		
 	} else {
-		memset(dest,0,AUDIO_BLOCK_SAMPLES * 2);
-		return;
+		memset(dest,0, sizeof(I2S3_tx_buffer) / 2);		
 	}
-
+	
+	#if IMXRT_CACHE_ENABLED >= 2		
+	arm_dcache_flush_delete(dest, sizeof(I2S3_tx_buffer) / 2 );
+	#endif
+	
 	if (offsetL < AUDIO_BLOCK_SAMPLES) {
 		AudioOutputMQS::block_left_offset = offsetL;
 	} else {

output_spdif.cpp

 uint16_t  AudioOutputSPDIF::block_left_offset = 0;
 uint16_t  AudioOutputSPDIF::block_right_offset = 0;
 bool AudioOutputSPDIF::update_responsibility = false;
-
-/* DMAMEM */ static uint32_t SPDIF_tx_buffer[AUDIO_BLOCK_SAMPLES * 4]; //2 KB
 DMAChannel AudioOutputSPDIF::dma(false);
+extern uint16_t spdif_bmclookup[256];
+DMAMEM __attribute__((aligned(32)))
+static uint32_t SPDIF_tx_buffer[AUDIO_BLOCK_SAMPLES * 4]; //2 KB
+
 
 #if defined(KINETISK) || defined(__IMXRT1052__) || defined(__IMXRT1062__)
 
 
 uint32_t  AudioOutputSPDIF::vucp = VUCP_VALID;
 
-static const
-uint16_t bmclookup[256] = { //biphase mark encoded values (least significant bit first)
-	0xcccc, 0x4ccc, 0x2ccc, 0xaccc, 0x34cc, 0xb4cc, 0xd4cc, 0x54cc,
-	0x32cc, 0xb2cc, 0xd2cc, 0x52cc, 0xcacc, 0x4acc, 0x2acc, 0xaacc,
-	0x334c, 0xb34c, 0xd34c, 0x534c, 0xcb4c, 0x4b4c, 0x2b4c, 0xab4c,
-	0xcd4c, 0x4d4c, 0x2d4c, 0xad4c, 0x354c, 0xb54c, 0xd54c, 0x554c,
-	0x332c, 0xb32c, 0xd32c, 0x532c, 0xcb2c, 0x4b2c, 0x2b2c, 0xab2c,
-	0xcd2c, 0x4d2c, 0x2d2c, 0xad2c, 0x352c, 0xb52c, 0xd52c, 0x552c,
-	0xccac, 0x4cac, 0x2cac, 0xacac, 0x34ac, 0xb4ac, 0xd4ac, 0x54ac,
-	0x32ac, 0xb2ac, 0xd2ac, 0x52ac, 0xcaac, 0x4aac, 0x2aac, 0xaaac,
-	0x3334, 0xb334, 0xd334, 0x5334, 0xcb34, 0x4b34, 0x2b34, 0xab34,
-	0xcd34, 0x4d34, 0x2d34, 0xad34, 0x3534, 0xb534, 0xd534, 0x5534,
-	0xccb4, 0x4cb4, 0x2cb4, 0xacb4, 0x34b4, 0xb4b4, 0xd4b4, 0x54b4,
-	0x32b4, 0xb2b4, 0xd2b4, 0x52b4, 0xcab4, 0x4ab4, 0x2ab4, 0xaab4,
-	0xccd4, 0x4cd4, 0x2cd4, 0xacd4, 0x34d4, 0xb4d4, 0xd4d4, 0x54d4,
-	0x32d4, 0xb2d4, 0xd2d4, 0x52d4, 0xcad4, 0x4ad4, 0x2ad4, 0xaad4,
-	0x3354, 0xb354, 0xd354, 0x5354, 0xcb54, 0x4b54, 0x2b54, 0xab54,
-	0xcd54, 0x4d54, 0x2d54, 0xad54, 0x3554, 0xb554, 0xd554, 0x5554,
-	0x3332, 0xb332, 0xd332, 0x5332, 0xcb32, 0x4b32, 0x2b32, 0xab32,
-	0xcd32, 0x4d32, 0x2d32, 0xad32, 0x3532, 0xb532, 0xd532, 0x5532,
-	0xccb2, 0x4cb2, 0x2cb2, 0xacb2, 0x34b2, 0xb4b2, 0xd4b2, 0x54b2,
-	0x32b2, 0xb2b2, 0xd2b2, 0x52b2, 0xcab2, 0x4ab2, 0x2ab2, 0xaab2,
-	0xccd2, 0x4cd2, 0x2cd2, 0xacd2, 0x34d2, 0xb4d2, 0xd4d2, 0x54d2,
-	0x32d2, 0xb2d2, 0xd2d2, 0x52d2, 0xcad2, 0x4ad2, 0x2ad2, 0xaad2,
-	0x3352, 0xb352, 0xd352, 0x5352, 0xcb52, 0x4b52, 0x2b52, 0xab52,
-	0xcd52, 0x4d52, 0x2d52, 0xad52, 0x3552, 0xb552, 0xd552, 0x5552,
-	0xccca, 0x4cca, 0x2cca, 0xacca, 0x34ca, 0xb4ca, 0xd4ca, 0x54ca,
-	0x32ca, 0xb2ca, 0xd2ca, 0x52ca, 0xcaca, 0x4aca, 0x2aca, 0xaaca,
-	0x334a, 0xb34a, 0xd34a, 0x534a, 0xcb4a, 0x4b4a, 0x2b4a, 0xab4a,
-	0xcd4a, 0x4d4a, 0x2d4a, 0xad4a, 0x354a, 0xb54a, 0xd54a, 0x554a,
-	0x332a, 0xb32a, 0xd32a, 0x532a, 0xcb2a, 0x4b2a, 0x2b2a, 0xab2a,
-	0xcd2a, 0x4d2a, 0x2d2a, 0xad2a, 0x352a, 0xb52a, 0xd52a, 0x552a,
-	0xccaa, 0x4caa, 0x2caa, 0xacaa, 0x34aa, 0xb4aa, 0xd4aa, 0x54aa,
-	0x32aa, 0xb2aa, 0xd2aa, 0x52aa, 0xcaaa, 0x4aaa, 0x2aaa, 0xaaaa
-};
 #endif
 
+PROGMEM
 void AudioOutputSPDIF::begin(void)
 {
 
 			sample = *src++;
 
 			//Subframe Channel 1
-			hi  = bmclookup[(uint8_t)(sample >> 8)];
-			lo  = bmclookup[(uint8_t) sample];
+			hi  = spdif_bmclookup[(uint8_t)(sample >> 8)];
+			lo  = spdif_bmclookup[(uint8_t) sample];
 			lo ^= (~((int16_t)hi) >> 16);
 			// 16 Bit sample:
 			*(dest+1) = ((uint32_t)lo << 16) | hi;
 			sample = *src++;
 
 			//Subframe Channel 2
-			hi  = bmclookup[(uint8_t)(sample >> 8)];
-			lo  = bmclookup[(uint8_t)sample];
+			hi  = spdif_bmclookup[(uint8_t)(sample >> 8)];
+			lo  = spdif_bmclookup[(uint8_t)sample];
 			lo ^= (~((int16_t)hi) >> 16);
 
 			*(dest+1) = ( ((uint32_t)lo << 16) | hi );
 		} while (dest < end);
 	}
 
+	#if IMXRT_CACHE_ENABLED >= 2
+	dest -= AUDIO_BLOCK_SAMPLES * 4/2 + 4/2;
+	arm_dcache_flush_delete(dest, sizeof(SPDIF_tx_buffer) / 2 );
+	#endif	
+	
 }
 
 void AudioOutputSPDIF::mute_PCM(const bool mute)
 #endif
 #endif
 
+PROGMEM
 void AudioOutputSPDIF::config_SPDIF(void)
 {
 #if defined(KINETISK)

output_spdif2.cpp

 
  // 2015/08/23: (FB) added mute_PCM() - sets or unsets VALID in VUCP (and adjusts PARITY)
 
+#if defined(__IMXRT1052__) || defined(__IMXRT1062__)
+ 
 #include <Arduino.h>
 #include "output_spdif2.h"
 #include "utility/imxrt_hw.h"
 uint16_t  AudioOutputSPDIF2::block_left_offset = 0;
 uint16_t  AudioOutputSPDIF2::block_right_offset = 0;
 bool AudioOutputSPDIF2::update_responsibility = false;
-
-/* DMAMEM */ static uint32_t SPDIF_tx_buffer[AUDIO_BLOCK_SAMPLES * 4]; //2 KB
 DMAChannel AudioOutputSPDIF2::dma(false);
+extern uint16_t spdif_bmclookup[256];
 
-#if defined(__IMXRT1052__) || defined(__IMXRT1062__)
+DMAMEM __attribute__((aligned(32)))
+static uint32_t SPDIF_tx_buffer[AUDIO_BLOCK_SAMPLES * 4]; //2 KB
 
 #define PREAMBLE_B  (0xE8) //11101000
 #define PREAMBLE_M  (0xE2) //11100010
 
 uint32_t  AudioOutputSPDIF2::vucp = VUCP_VALID;
 
-static const
-uint16_t bmclookup[256] = { //biphase mark encoded values (least significant bit first)
-	0xcccc, 0x4ccc, 0x2ccc, 0xaccc, 0x34cc, 0xb4cc, 0xd4cc, 0x54cc,
-	0x32cc, 0xb2cc, 0xd2cc, 0x52cc, 0xcacc, 0x4acc, 0x2acc, 0xaacc,
-	0x334c, 0xb34c, 0xd34c, 0x534c, 0xcb4c, 0x4b4c, 0x2b4c, 0xab4c,
-	0xcd4c, 0x4d4c, 0x2d4c, 0xad4c, 0x354c, 0xb54c, 0xd54c, 0x554c,
-	0x332c, 0xb32c, 0xd32c, 0x532c, 0xcb2c, 0x4b2c, 0x2b2c, 0xab2c,
-	0xcd2c, 0x4d2c, 0x2d2c, 0xad2c, 0x352c, 0xb52c, 0xd52c, 0x552c,
-	0xccac, 0x4cac, 0x2cac, 0xacac, 0x34ac, 0xb4ac, 0xd4ac, 0x54ac,
-	0x32ac, 0xb2ac, 0xd2ac, 0x52ac, 0xcaac, 0x4aac, 0x2aac, 0xaaac,
-	0x3334, 0xb334, 0xd334, 0x5334, 0xcb34, 0x4b34, 0x2b34, 0xab34,
-	0xcd34, 0x4d34, 0x2d34, 0xad34, 0x3534, 0xb534, 0xd534, 0x5534,
-	0xccb4, 0x4cb4, 0x2cb4, 0xacb4, 0x34b4, 0xb4b4, 0xd4b4, 0x54b4,
-	0x32b4, 0xb2b4, 0xd2b4, 0x52b4, 0xcab4, 0x4ab4, 0x2ab4, 0xaab4,
-	0xccd4, 0x4cd4, 0x2cd4, 0xacd4, 0x34d4, 0xb4d4, 0xd4d4, 0x54d4,
-	0x32d4, 0xb2d4, 0xd2d4, 0x52d4, 0xcad4, 0x4ad4, 0x2ad4, 0xaad4,
-	0x3354, 0xb354, 0xd354, 0x5354, 0xcb54, 0x4b54, 0x2b54, 0xab54,
-	0xcd54, 0x4d54, 0x2d54, 0xad54, 0x3554, 0xb554, 0xd554, 0x5554,
-	0x3332, 0xb332, 0xd332, 0x5332, 0xcb32, 0x4b32, 0x2b32, 0xab32,
-	0xcd32, 0x4d32, 0x2d32, 0xad32, 0x3532, 0xb532, 0xd532, 0x5532,
-	0xccb2, 0x4cb2, 0x2cb2, 0xacb2, 0x34b2, 0xb4b2, 0xd4b2, 0x54b2,
-	0x32b2, 0xb2b2, 0xd2b2, 0x52b2, 0xcab2, 0x4ab2, 0x2ab2, 0xaab2,
-	0xccd2, 0x4cd2, 0x2cd2, 0xacd2, 0x34d2, 0xb4d2, 0xd4d2, 0x54d2,
-	0x32d2, 0xb2d2, 0xd2d2, 0x52d2, 0xcad2, 0x4ad2, 0x2ad2, 0xaad2,
-	0x3352, 0xb352, 0xd352, 0x5352, 0xcb52, 0x4b52, 0x2b52, 0xab52,
-	0xcd52, 0x4d52, 0x2d52, 0xad52, 0x3552, 0xb552, 0xd552, 0x5552,
-	0xccca, 0x4cca, 0x2cca, 0xacca, 0x34ca, 0xb4ca, 0xd4ca, 0x54ca,
-	0x32ca, 0xb2ca, 0xd2ca, 0x52ca, 0xcaca, 0x4aca, 0x2aca, 0xaaca,
-	0x334a, 0xb34a, 0xd34a, 0x534a, 0xcb4a, 0x4b4a, 0x2b4a, 0xab4a,
-	0xcd4a, 0x4d4a, 0x2d4a, 0xad4a, 0x354a, 0xb54a, 0xd54a, 0x554a,
-	0x332a, 0xb32a, 0xd32a, 0x532a, 0xcb2a, 0x4b2a, 0x2b2a, 0xab2a,
-	0xcd2a, 0x4d2a, 0x2d2a, 0xad2a, 0x352a, 0xb52a, 0xd52a, 0x552a,
-	0xccaa, 0x4caa, 0x2caa, 0xacaa, 0x34aa, 0xb4aa, 0xd4aa, 0x54aa,
-	0x32aa, 0xb2aa, 0xd2aa, 0x52aa, 0xcaaa, 0x4aaa, 0x2aaa, 0xaaaa
-};
-
+PROGMEM
 void AudioOutputSPDIF2::begin(void)
 {
 
 		end = (int32_t *)&SPDIF_tx_buffer[AUDIO_BLOCK_SAMPLES * 4/2];
 	}
 
-
 	block = AudioOutputSPDIF2::block_left_1st;
 	if (block) {
 		offset = AudioOutputSPDIF2::block_left_offset;
 			sample = *src++;
 
 			//Subframe Channel 1
-			hi  = bmclookup[(uint8_t)(sample >> 8)];
-			lo  = bmclookup[(uint8_t) sample];
+			hi  = spdif_bmclookup[(uint8_t)(sample >> 8)];
+			lo  = spdif_bmclookup[(uint8_t) sample];
 			lo ^= (~((int16_t)hi) >> 16);
 			// 16 Bit sample:
 			*(dest+1) = ((uint32_t)lo << 16) | hi;
 			sample = *src++;
 
 			//Subframe Channel 2
-			hi  = bmclookup[(uint8_t)(sample >> 8)];
-			lo  = bmclookup[(uint8_t)sample];
+			hi  = spdif_bmclookup[(uint8_t)(sample >> 8)];
+			lo  = spdif_bmclookup[(uint8_t)sample];
 			lo ^= (~((int16_t)hi) >> 16);
 
 			*(dest+1) = ( ((uint32_t)lo << 16) | hi );
 		} while (dest < end);
 	}
 
+	#if IMXRT_CACHE_ENABLED >= 2
+	dest -= AUDIO_BLOCK_SAMPLES * 4/2 + 4/2;
+	arm_dcache_flush_delete(dest, sizeof(SPDIF_tx_buffer) / 2 );
+	#endif
+
 }
 
 void AudioOutputSPDIF2::mute_PCM(const bool mute)
 
 }
 
+PROGMEM
 void AudioOutputSPDIF2::config_SPDIF(void)
 {
 	CCM_CCGR5 |= CCM_CCGR5_SAI2(CCM_CCGR_ON);
 }
 
 
-#else
-
-void AudioOutputSPDIF2::update(void)
-{
-
-	audio_block_t *block;
-	block = receiveReadOnly(0); // input 0 = left channel
-	if (block) release(block);
-	block = receiveReadOnly(1); // input 1 = right channel
-	if (block) release(block);
-}
 
 #endif

output_spdif3.cpp

+/* Hardware-SPDIF for Teensy 4
+ * Copyright (c) 2019, Frank Bösing, f.boesing@gmx.de
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice, development funding notice, and this permission
+ * notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+/*
+ http://www.hardwarebook.info/S/PDIF
+ https://www.mikrocontroller.net/articles/S/PDIF
+ https://en.wikipedia.org/wiki/S/PDIF
+*/
+
+#if defined(__IMXRT1052__) || defined(__IMXRT1062__)
+
+#include <Arduino.h>
+#include "output_spdif3.h"
+#include "utility/imxrt_hw.h"
+#include "memcpy_audio.h"
+#include <math.h>
+
+audio_block_t * AudioOutputSPDIF3::block_left_1st = nullptr;
+audio_block_t * AudioOutputSPDIF3::block_right_1st = nullptr;
+audio_block_t * AudioOutputSPDIF3::block_left_2nd = nullptr;
+audio_block_t * AudioOutputSPDIF3::block_right_2nd = nullptr;
+bool AudioOutputSPDIF3::update_responsibility = false;
+DMAChannel AudioOutputSPDIF3::dma(false);
+
+DMAMEM  __attribute__((aligned(32)))
+static int32_t SPDIF_tx_buffer[AUDIO_BLOCK_SAMPLES * 4];
+DMAMEM  __attribute__((aligned(32)))
+audio_block_t AudioOutputSPDIF3::block_silent;
+
+PROGMEM
+void AudioOutputSPDIF3::begin(void)
+{
+
+	dma.begin(true); // Allocate the DMA channel first
+
+	block_left_1st = nullptr;
+	block_right_1st = nullptr;
+	memset(&block_silent, 0, sizeof(block_silent));
+	uint32_t fs = AUDIO_SAMPLE_RATE_EXACT;
+	// PLL between 27*24 = 648MHz und 54*24=1296MHz
+	// n1, n2 choosen for compatibility with I2S (same PLL frequency) :
+	int n1 = 4; //SAI prescaler 4 => (n1*n2) = multiple of 4
+	int n2 = 1 + (24000000 * 27) / (fs * 256 * n1);
+	double C = ((double)fs * 256 * n1 * n2) / 24000000;
+	int c0 = C;
+	int c2 = 10000;
+	int c1 = C * c2 - (c0 * c2);
+	set_audioClock(c0, c1, c2);
+
+	double pllclock = (c0 + (double)c1 / c2) * 24000000; //677376000 Hz
+
+	//use new pred/podf values
+	n1 = 7; //0: divide by 1 (do not use with high input frequencies), 1:/2, 2: /3, 7:/8
+	n2 = 0; //0: divide by 1, 7: divide by 8
+
+	uint32_t clock = pllclock / (1 + n1) / (1 + n2);
+	uint32_t clkdiv = clock / (fs * 64); // 1 .. 128
+	uint32_t mod = clock % (fs * 64);
+	if (mod > ((fs * 64) / 2)) clkdiv += 1; //nearest divider
+
+	CCM_CCGR5 &= ~CCM_CCGR5_SPDIF(CCM_CCGR_ON); //Clock gate off
+
+	CCM_CDCDR = (CCM_CDCDR & ~(CCM_CDCDR_SPDIF0_CLK_SEL_MASK | CCM_CDCDR_SPDIF0_CLK_PRED_MASK | CCM_CDCDR_SPDIF0_CLK_PODF_MASK))
+		| CCM_CDCDR_SPDIF0_CLK_SEL(0) // 0 PLL4, 1 PLL3 PFD2, 2 PLL5, 3 pll3_sw_clk
+		| CCM_CDCDR_SPDIF0_CLK_PRED(n1)
+		| CCM_CDCDR_SPDIF0_CLK_PODF(n2);
+
+	CCM_CCGR5 |= CCM_CCGR5_SPDIF(CCM_CCGR_ON); //Clock gate on
+
+	if ((SPDIF_SCR & 0x400) != 0) {			//If default value:
+		SPDIF_SCR = SPDIF_SCR_SOFT_RESET;		//Reset SPDIF
+		while (SPDIF_SCR & SPDIF_SCR_SOFT_RESET) {;}	//Wait for Reset (takes 8 cycles)
+		SPDIF_SCR = 0;
+	}
+
+	SPDIF_SCR |=
+		SPDIF_SCR_RXFIFOFULL_SEL(0) |// Full interrupt if at least 1 sample in Rx left and right FIFOs
+		SPDIF_SCR_RXAUTOSYNC |
+		SPDIF_SCR_TXAUTOSYNC |
+		SPDIF_SCR_TXFIFOEMPTY_SEL(3) | // Empty interrupt if at most 4 sample in Tx left and right FIFOs
+		SPDIF_SCR_TXFIFO_CTRL(1) | // 0:Send zeros 1: normal operation
+		SPDIF_SCR_DMA_TX_EN |
+		//SPDIF_SCR_VALCTRL | // Outgoing Validity always clear
+		SPDIF_SCR_TXSEL(5) | //0:off and output 0, 1:Feed-though SPDIFIN, 5:Tx Normal operation
+		SPDIF_SCR_USRC_SEL(3); // No embedded U channel
+		SPDIF_SRCD = 0;
+		SPDIF_STCSCH = 0;
+		SPDIF_STCSCL = 0;
+	
+	SPDIF_SRCD = 0;
+
+	SPDIF_STC = SPDIF_STC_TXCLK_SOURCE(1) //tx_clk input (from SPDIF0_CLK_ROOT)
+		| SPDIF_STC_SYSCLK_DF(0)
+		| SPDIF_STC_TXCLK_DF(clkdiv - 1);
+
+	const int nbytes_mlno = 2 * 4; // 8 Bytes per minor loop
+
+	dma.TCD->SADDR = SPDIF_tx_buffer;
+	dma.TCD->SOFF = 4;
+	dma.TCD->ATTR = DMA_TCD_ATTR_SSIZE(2) | DMA_TCD_ATTR_DSIZE(2);	
+	dma.TCD->NBYTES_MLNO = DMA_TCD_NBYTES_MLOFFYES_NBYTES(nbytes_mlno) | DMA_TCD_NBYTES_DMLOE | 
+                         DMA_TCD_NBYTES_MLOFFYES_MLOFF(-8);
+	dma.TCD->SLAST = -sizeof(SPDIF_tx_buffer);
+	dma.TCD->DADDR = &SPDIF_STL;
+	dma.TCD->DOFF = 4;
+	dma.TCD->DLASTSGA = -8;
+	//dma.TCD->ATTR_DST = ((31 - __builtin_clz(8)) << 3);
+	dma.TCD->CITER_ELINKNO = sizeof(SPDIF_tx_buffer) / nbytes_mlno;	
+	dma.TCD->BITER_ELINKNO = sizeof(SPDIF_tx_buffer) / nbytes_mlno;
+	dma.TCD->CSR = DMA_TCD_CSR_INTHALF | DMA_TCD_CSR_INTMAJOR;
+
+	dma.triggerAtHardwareEvent(DMAMUX_SOURCE_SPDIF_TX);
+
+	update_responsibility = update_setup();	
+	dma.enable();
+	dma.attachInterrupt(isr);	
+
+	CORE_PIN14_CONFIG = 3;  //3:SPDIF_OUT
+	SPDIF_STC |= SPDIF_STC_TX_ALL_CLK_EN;
+//	pinMode(13, OUTPUT);
+}
+
+void AudioOutputSPDIF3::isr(void)
+{
+
+	const int16_t *src_left, *src_right;
+	const int32_t *end;
+	int32_t *dest;
+	audio_block_t *block_left, *block_right;
+	uint32_t saddr;
+
+	saddr = (uint32_t)(dma.TCD->SADDR);
+	dma.clearInterrupt();
+	if (saddr < (uint32_t)SPDIF_tx_buffer + sizeof(SPDIF_tx_buffer) / 2) {
+		// DMA is transmitting the first half of the buffer
+		// so we must fill the second half
+		dest = SPDIF_tx_buffer + AUDIO_BLOCK_SAMPLES*2;
+		end = SPDIF_tx_buffer + AUDIO_BLOCK_SAMPLES*4;
+	} else {
+		// DMA is transmitting the second half of the buffer
+		// so we must fill the first half
+		dest = SPDIF_tx_buffer;
+		end = SPDIF_tx_buffer + AUDIO_BLOCK_SAMPLES*2;
+	}
+	block_left = block_left_1st;
+	if (!block_left) block_left = &block_silent;
+	block_right = block_right_1st;
+	if (!block_right) block_right = &block_silent;
+
+	src_left = (const int16_t *)(block_left->data);
+	src_right = (const int16_t *)(block_right->data);
+		
+	do {
+		
+		*dest++ = (*src_left++) << 8;
+		*dest++ = (*src_right++) << 8;
+
+		*dest++ = (*src_left++) << 8;
+		*dest++ = (*src_right++) << 8;
+		
+		*dest++ = (*src_left++) << 8;
+		*dest++ = (*src_right++) << 8;
+
+		*dest++ = (*src_left++) << 8;
+		*dest++ = (*src_right++) << 8;
+		
+		#if IMXRT_CACHE_ENABLED >= 2
+		SCB_CACHE_DCCIMVAC = (uint32_t) dest - 32;
+		#endif
+		
+	} while (dest < end);
+	
+	if (block_left != &block_silent) {
+		release(block_left);	
+		block_left_1st = block_left_2nd;
+		block_left_2nd = nullptr;
+	}
+	if (block_right != &block_silent) {
+		release(block_right);	
+		block_right_1st = block_right_2nd;
+		block_right_2nd = nullptr;
+	}
+
+	if (update_responsibility) update_all();
+	//digitalWriteFast(13,!digitalReadFast(13));	
+}
+
+void AudioOutputSPDIF3::update(void)
+{
+	audio_block_t *block_left, *block_right;
+
+	block_left = receiveReadOnly(0);  // input 0
+	block_right = receiveReadOnly(1); // input 1
+	__disable_irq();
+	if (block_left) {
+		if (block_left_1st == nullptr) {
+			block_left_1st = block_left;
+			block_left = nullptr;
+		} else if (block_left_2nd == nullptr) {
+			block_left_2nd = block_left;
+			block_left = nullptr;
+		} else {
+			audio_block_t *tmp = block_left_1st;
+			block_left_1st = block_left_2nd;
+			block_left_2nd = block_left;
+			block_left = tmp;
+		}
+	}
+	if (block_right) {
+		if (block_right_1st == nullptr) {
+			block_right_1st = block_right;
+			block_right = nullptr;
+		} else if (block_right_2nd == nullptr) {
+			block_right_2nd = block_right;
+			block_right = nullptr;
+		} else {
+			audio_block_t *tmp = block_right_1st;
+			block_right_1st = block_right_2nd;
+			block_right_2nd = block_right;
+			block_right = tmp;
+		}
+	}
+	__enable_irq();
+	if (block_left) {
+		release(block_left);	
+	}
+	if (block_right) {			
+		release(block_right);		
+	}
+
+}
+
+void AudioOutputSPDIF3::mute_PCM(const bool mute)
+{
+	if (mute)
+		SPDIF_SCR |= SPDIF_SCR_VALCTRL;		
+	else
+		SPDIF_SCR &= ~SPDIF_SCR_VALCTRL;
+}
+#endif

output_spdif3.h

+/* Hardware-SPDIF for Teensy 4
+ * Copyright (c) 2019, Frank Bösing, f.boesing@gmx.de
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice, development funding notice, and this permission
+ * notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef output_SPDIF3_h_
+#define output_SPDIF3_h_
+
+#include <Arduino.h>
+#include <AudioStream.h>
+#include <DMAChannel.h>
+
+class AudioOutputSPDIF3 : public AudioStream
+{
+public:
+	AudioOutputSPDIF3(void) : AudioStream(2, inputQueueArray) { begin(); }
+	virtual void update(void);
+	void begin(void);
+	//friend class AudioInputSPDIF;
+	static void mute_PCM(const bool mute);
+protected:
+	//AudioOutputSPDIF3(int dummy): AudioStream(2, inputQueueArray) {}
+	static audio_block_t *block_left_1st;
+	static audio_block_t *block_right_1st;
+	static bool update_responsibility;
+	static DMAChannel dma;
+	static void isr(void);
+private:
+	static audio_block_t *block_left_2nd;
+	static audio_block_t *block_right_2nd;
+	static audio_block_t block_silent;
+	audio_block_t *inputQueueArray[2];
+};
+
+
+#endif

utility/imxrt_hw.cpp

 	CCM_ANALOG_PLL_AUDIO = 0;
 	//CCM_ANALOG_PLL_AUDIO |= CCM_ANALOG_PLL_AUDIO_BYPASS;
 	CCM_ANALOG_PLL_AUDIO |= CCM_ANALOG_PLL_AUDIO_ENABLE
-			     | CCM_ANALOG_PLL_AUDIO_POST_DIV_SELECT(2) // 0: 1/4; 1: 1/2; 0: 1/1
+			     | CCM_ANALOG_PLL_AUDIO_POST_DIV_SELECT(2) // 2: 1/4; 1: 1/2; 0: 1/1
 			     | CCM_ANALOG_PLL_AUDIO_DIV_SELECT(nfact);
 
 	CCM_ANALOG_PLL_AUDIO_NUM   = nmult & CCM_ANALOG_PLL_AUDIO_NUM_MASK;

utility/imxrt_hw.h

 #ifndef imxr_hw_h_
 #define imxr_hw_h_
 
+#define IMXRT_CACHE_ENABLED 2 // 0=disabled, 1=WT, 2= WB
+
 #include <Arduino.h>
 #include <imxrt.h>
 
 void set_audioClock(int nfact, int32_t nmult, uint32_t ndiv); // sets PLL4
 
 #endif
+
+#else
+//No IMXRT
+#define IMXRT_CACHE_ENABLED 0
 #endif
+