This audio adaptor lets you easily add high quality 16 bit, 44.1 kHz sample rate (CD quality) audio to your projects with the Teensy 4.0 (Rev D). It supports stereo headphone and stereo line-level output, and also stereo line-level input or mono microphone input.
The Teensy Audio Library lets you use the input and output simultaneously together with a toolkit of audio processing objects, to easily create all types of sophisticated audio applications. You can play multiple sound files, create synthesized waveforms, apply effects, mix multiple streams and output high-quality audio to the headphones or line out pins.
| Function | Teensy 4.0 Pins Rev D | Shareable |
| Audio Data | 7, 8, 20, 21, 23 | |
| Audio Control | 18, 19 | SDA, SCL (other I2C chips) |
| Volume Pot | 15 (A1) | |
| SD Card | 10, 11, 12, 13 | MOSI, MISO, SCK (other SPI chips) |
| Memory Chip | 6, 11, 12, 13 | MOSI, MISO, SCK (other SPI chips) |
The audio chip, part number SGTL5000, connects to Teensy using 7 signals. The I2C pins SDA and SCL are used to control the chip and adjust parameters. Audio data uses I2S signals, TX (to headphones and/or line out) and RX (from line-in or mic), and 3 clocks, LRCLK (44.1 kHz), BCLK (1.41MHz) and MCLK (11.29 MHz).
| Signal | Rev D (Teensy 4.0) | Function |
| MCLK | 23 | Audio Master Clock, 11.29MHz |
| BCLK | 21 |