Teensy 4 I2S Library

This is a no-nonsense I2S library for Teensy 4 and 4.1. It was derived from the I2S code in Paul Stoffregen's Teensy Audio Library but has been stripped down to nothing but the I2S code and some basic support mechanisms.

Features

• 16/24/32 Bit, 44.1/48/96 Khz audio processing
• Completely stand-alone library, does not depend on the Teensy Audio library.
• Retains some of the Codec controllers from the Audio Library
• Adds codec controller for TI TLV320AIC3204

Pinout

Required pinout is the same as the Teensy Audio Board and the Teensy Audio library

MCLK    23      Audio Master Clock - Speed: 256 * Fs
BCLK    21      Audio Bit Clock (aka. Serial Clock / SCLK) - Speed: 64 * Fs
LRCLK   20      Audio Left/Right Clock (aka. Word Clock / WCLK) - Speed: Fs
DIN     7       Audio Data from Teensy to Codec
DOUT    8       Audio Data from Codex to Teensy
SCL     19      I2C Control Clock
SDA     18      I2C Control Data

Frequencies

At 44.1Khz:

MCLK    11.289,600 Mhz
BCLK    2.822,400 Mhz
LRCLK   44.1 Khz

At 48Khz:

MCLK    12.288 Mhz
BCLK    3.072 Mhz
LRCLK   48.0 Khz

Notes

Please note that the library always transmits and receives 32 bits between the codec and Teensy. Please ensure you shift your input and output values appropriately in code to work at your desired bit depth. For example, for 24 bit data, you must multiply output data by 256, or left-shift by 8 bits. Similarly, for input data, you must right shift by 8 bits or divide by 256 to obtain a 24 bit value.