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- /* 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);
- #if IMXRT_CACHE_ENABLED > 0
- SCB_CACHE_DCCIMVAC = (uint32_t)block_left;
- #endif
- block_left_1st = block_left_2nd;
- block_left_2nd = nullptr;
- }
- if (block_right != &block_silent) {
- release(block_right);
- #if IMXRT_CACHE_ENABLED > 0
- SCB_CACHE_DCCIMVAC = (uint32_t)block_right;
- #endif
- 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 IMXRT_CACHE_ENABLED > 0
- SCB_CACHE_DCCIMVAC = (uint32_t)block_left;
- #endif
- }
- if (block_right) {
- release(block_right);
- #if IMXRT_CACHE_ENABLED > 0
- SCB_CACHE_DCCIMVAC = (uint32_t)block_right;
- #endif
- }
-
- }
-
- void AudioOutputSPDIF3::mute_PCM(const bool mute)
- {
- if (mute)
- SPDIF_SCR |= SPDIF_SCR_VALCTRL;
- else
- SPDIF_SCR &= ~SPDIF_SCR_VALCTRL;
- }
- #endif
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