Multichannel USB audio play and record

teensy4/AudioRate.h

@@ -0,0 +1,162 @@
+/* Teensyduino Core Library
+ * http://www.pjrc.com/teensy/
+ * Copyright (c) 2017 PJRC.COM, LLC.
+ *
+ * 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:
+ *
+ * 1. The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * 2. If the Software is incorporated into a build system that allows
+ * selection among a list of target devices, then similar target
+ * devices manufactured by PJRC.COM must be included in the list of
+ * target devices and selectable in the same manner.
+ *
+ * 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 AudioRate_h
+#define AudioRate_h
+
+#ifndef AUDIO_SAMPLE_RATE
+#define AUDIO_SAMPLE_RATE (44100)
+#endif
+
+#ifdef AUDIO_SAMPLE_RATE_EXACT
+#error You must set AUDIO_SAMPLE_RATE to an integer, not AUDIO_SAMPLE_RATE_EXACT to a float. This is a change due to preprocess #if rate== stuff. Probably can be worked around, but this is expedient.
+#endif
+
+#define AUDIO_SAMPLE_RATE_EXACT (AUDIO_SAMPLE_RATE * 1.0f)
+
+#ifndef USB_AUDIO_TX_CHANNELS
+#define USB_AUDIO_TX_CHANNELS (2U) /* NUMBER OF CHANNELS IN ISO_IN transactions */
+#endif
+
+#ifndef USB_AUDIO_RX_CHANNELS
+#define USB_AUDIO_RX_CHANNELS (2U) /* NUMBER OF CHANNELS IN ISO_OUT transactions */
+#endif
+
+#ifndef USB_AUDIO_BYTES_PER_SAMPLE
+#define USB_AUDIO_BYTES_PER_SAMPLE 2
+#endif
+
+// The number of RX data pins used for SAI reception. 
+// SAI1 on teensy 4 has 4 possible pins for each of TX/RX
+// They are shared, and can't be used simultaneously.
+// On Teensy They are
+
+// pin# | TEENSY | USE | PAD
+// | NAME | |
+//-------|---------|---------|---------- 
+// 7 | OUT1A | TX1 | GPIO_B1_01_ALT3
+// 32 | OUT1B | TX2 RX4 | GPIO_B0_12_ALT3
+// 9 | OUT1C | TX3 RX3 | GPIO_B0_11_ALT3
+// 6 | OUT1D | TX4 RX2 | GPIO_B0_10_ALT3
+// 8 | IN1 | RX1 | GPIO_B1_00_ALT3
+#ifndef AUDIO_N_SAI1_RX_DATAPINS
+#define AUDIO_N_SAI1_RX_DATAPINS 1
+#endif
+
+#ifndef AUDIO_N_SAI1_TX_DATAPINS
+#define AUDIO_N_SAI1_TX_DATAPINS 1
+#endif
+
+# if (AUDIO_N_SAI1_RX_DATAPINS > 4 || AUDIO_N_SAI1_RX_DATAPINS < 1)
+#error SAI1 may have between 1 and 4 (inclusive) data pins for RX
+#endif
+# if (AUDIO_N_SAI1_TX_DATAPINS > 4 || AUDIO_N_SAI1_TX_DATAPINS < 1)
+#error SAI1 may have between 1 and 4 (inclusive) data pins for TX
+#endif
+
+#if (AUDIO_N_SAI1_RX_DATAPINS + AUDIO_N_SAI1_TX_DATAPINS > 5)
+#error SAI1 has only 5 data pins. You ve asked for too many.
+#endif
+
+#define USB_AUDIO_BYTES_PER_SAMPLE 2 /* warning... don't change this... it's not easily changeable yet, */
+#define USB_AUDIO_BYTES_PER_TX_FRAME (USB_AUDIO_TX_CHANNELS*USB_AUDIO_BYTES_PER_SAMPLE)
+#define USB_AUDIO_BYTES_PER_RX_FRAME (USB_AUDIO_RX_CHANNELS*USB_AUDIO_BYTES_PER_SAMPLE)
+
+/* This isn't a parameter... yet. Don't change it.. */
+#define TDM_CHANNELS_PER_PIN 16
+
+/*
+ AUDIO_TX_SIZE and AUDIO_RX_SIZE are the maximum TX and RX sizes
+ respectively, IN BYTES. 
+
+ for 44.1khz, 16-bits, the number of bytes per 1ms usb frame is
+ 44100 af sec 2 channels 2 bytes 176.4 bytes
+ ----------- * -------- * ---------- * ------------ = -----------
+ sec 1000 uf audio_frame sample uf
+
+ where:
+ af : audio_frame (i.e. what you typically call a sample)
+ sample : an actual, single sample representing one channel, at one time
+ uf : usb frame. 1khz for full speed
+ channel: channel is made up of 1 sample for every channel in the stream
+
+ for 44.1khz, you must transmit an average of 176.4 bytes, which is
+ 44.1 audio_frame per usb_frame, so sometimes you need to transmit 44
+ and somteims you need to transmit 45. So buffer sizes need to be 
+
+ 45 * 2 channels * 2 bytes = 180 bytes.
+
+ For 48000, it's exactly 48000/1000 = 48 audio_frames/usb_frame.
+ Unfortunately, the USB 1khz rate isn't exactly the same as the
+ audio's 1khz rate, so you might sometimes need to transmit one extra
+ 'makeup' frame sometimes, depening on the synchronization method.
+
+ In which case it would be
+ (48+1) audio_frames * 2 channels * 2 bytes = 192 bytes
+*/
+
+#if AUDIO_SAMPLE_RATE == 44100
+ #define AUDIO_BASEFRAMES (44)
+// Send an extra frame every 10 usb frames */
+ #define AUDIO_BASEFRAMES_EXTRA (10)
+#elif AUDIO_SAMPLE_RATE == 48000
+#define AUDIO_BASEFRAMES (48)
+#elif AUDIO_SAMPLE_RATE == 32000
+ #define AUDIO_BASEFRAMES (32)
+#elif AUDIO_SAMPLE_RATE == 16000
+ #define AUDIO_BASEFRAMES (16)
+#elif AUDIO_SAMPLE_RATE == 8000
+ #define AUDIO_BASEFRAMES (8)
+#else
+#error UNSUPPORTED SAMPLE RATE, or you have specified a FLOAT. Currently supported rates are 44100, 48000, 32000, 16000, 8000. Set AUDIO_SAMPLE_RATE=<one of the above>
+#endif
+
+#ifndef AUDIO_BASEFRAMES_EXTRA
+// the even multiples of 1kHz don't need any extra frames typically.
+#define AUDIO_BASEFRAMES_EXTRA 0
+#endif
+
+// We still need a +1 to BASEFRAMES because we still need the ability to transmit
+// one extra frame when the USB host is consuming frames too quickly.
+#define AUDIO_TX_SIZE ((AUDIO_BASEFRAMES+1) * USB_AUDIO_TX_CHANNELS * USB_AUDIO_BYTES_PER_SAMPLE)
+#define AUDIO_RX_SIZE ((AUDIO_BASEFRAMES+1) * USB_AUDIO_RX_CHANNELS * USB_AUDIO_BYTES_PER_SAMPLE)
+
+#ifndef AUDIO_N_SAI1_RX_DATAPINS
+# define AUDIO_N_SAI1_RX_DATAPINS (1)
+#endif
+
+#ifndef AUDIO_N_SAI1_TX_DATAPINS
+# define AUDIO_N_SAI1_TX_DATAPINS (1)
+#endif
+
+#ifndef TDM_CHANNELS_PER_PIN
+#define TDM_CHANNELS_PER_PIN (16)
+#endif
+
+#endif

teensy4/AudioStream.h

@@ -54,11 +54,7 @@
 #define AUDIO_BLOCK_SAMPLES 128
 #endif
 
-#ifndef AUDIO_SAMPLE_RATE_EXACT
-#define AUDIO_SAMPLE_RATE_EXACT 44100.0f
-#endif
-
-#define AUDIO_SAMPLE_RATE AUDIO_SAMPLE_RATE_EXACT
+#include "AudioRate.h"
 
 #define noAUDIO_DEBUG_CLASS // disable this class by default
 

teensy4/imxrt.h

@@ -8395,6 +8395,11 @@ typedef struct {
 #define I2S_RCR4_SYWD(n) ((uint32_t)((n) & 0x1f)<<8) // Sync Width
 #define I2S_RCR4_FRSZ(n) ((uint32_t)((n) & 0x0f)<<16) // Frame Size
 #define I2S_RCR4_FCONT ((uint32_t)1<<28) // FIFO Continue on Error
+#define I2S_RCR4_FCOMB(n) ((uint32_t)(n & 0x3)<<26) // FIFO Combine Mode
+#define I2S_RCR4_FCOMB_DISABLED I2S_RCR4_FCOMB(0) // No FIFO combining
+#define I2S_RCR4_FCOMB_ENABLED_ON_WRITES I2S_RCR4_FCOMB(1) // <-- this is the one you want.
+#define I2S_RCR4_FCOMB_ENABLED_ON_READS I2S_RCR4_FCOMB(2) 
+#define I2S_RCR4_FCOMB_ENABLED_ON_RW I2S_RCR4_FCOMB(3)
 #define I2S_RCR5_FBT(n) ((uint32_t)((n) & 0x1f)<<8) // First Bit Shifted
 #define I2S_RCR5_W0W(n) ((uint32_t)((n) & 0x1f)<<16) // Word 0 Width
 #define I2S_RCR5_WNW(n) ((uint32_t)((n) & 0x1f)<<24) // Word N Width
@@ -8419,6 +8424,11 @@ typedef struct {
 #define I2S_TCR4_SYWD(n) ((uint32_t)((n) & 0x1f)<<8) // Sync Width
 #define I2S_TCR4_FRSZ(n) ((uint32_t)((n) & 0x0f)<<16) // Frame Size
 #define I2S_TCR4_FCONT ((uint32_t)1<<28) // FIFO Continue on Error
+#define I2S_TCR4_FCOMB(n) ((uint32_t)(n & 0x3)<<26) // FIFO Combine Mode
+#define I2S_TCR4_FCOMB_DISABLED I2S_TCR4_FCOMB(0)
+#define I2S_TCR4_FCOMB_ENABLED_ON_READS I2S_TCR4_FCOMB(1) // <--- this is the one you want
+#define I2S_TCR4_FCOMB_ENABLED_ON_WRITES I2S_TCR4_FCOMB(2)
+#define I2S_TCR4_FCOMB_ENABLED_ON_RW I2S_TCR4_FCOMB(3)
 #define I2S_TCR5_FBT(n) ((uint32_t)((n) & 0x1f)<<8) // First Bit Shifted
 #define I2S_TCR5_W0W(n) ((uint32_t)((n) & 0x1f)<<16) // Word 0 Width
 #define I2S_TCR5_WNW(n) ((uint32_t)((n) & 0x1f)<<24) // Word N Width