Pinouts and wiring for hard wiring as opposed to stacking.
| Audio Shield Signal | Rev D, D2 (Teensy 4.x) | Rev C (Teensy 3.x) | Required For | Function |
|---|---|---|---|---|
| MCLK | 23 (MCLK1) | 11 (MCLK) | Audio | Audio Master Clock, 11.29 MHz |
| BCLK | 21 (BCLK1) | 9 (BCLK) | Audio | Audio Bit Clock, 1.41 or 2.82 MHz |
| LRCLK | 20 (LRCLK1) | 23 (LRCLK) | Audio | Audio Left/Right Clock, 44.1 kHz |
| DIN | 7 (OUT1A) | 22 (OUT) | Audio Output | Audio Data from Teensy to Audio Shield Goes to both headphone jack and Line-Out pins |
| DOUT | 8 (IN1) | 13 (IN) | Audio Input | Audio Data from Audio Shield to Teensy Comes from either Microphone or Line-In pins |
| SCL | 19 | 19 | Audio Config | Control Clock (I2C) |
| SDA | 18 | 18 | Audio Config | Control Data (I2C) |
| SCK | 13 | 14 | Optional Data SD or MEM | Data Storage (SPI) Clock |
| MISO | 12 | 12 | Optional Data SD or MEM | Data Storage (SPI) from SD/MEM to Teensy |
| MOSI | 11 | 7 | Optional Data SD or MEM | Data Storage (SPI) from Teensy to SD/MEM |
| SDCS | 10 | 10 | Optional Data SD Card | Chip Select (SPI) for SD Card |
| MEMCS | 6 | 6 | Optional Data MEM Chip | Chip Select (SPI) for Memory Chip |
| Vol | 15 / A1 | 15 / A1 | Optional Knob | Volume Thumbwheel (analog signal) |
GND — connect at least one GND from the Teensy to a GND pad on the shield. There are multiple GNDs available on each; using two (one near power, one near signal) helps reduce noise.
I²S (audio bus) — the five teal wires carry the actual audio. MCLK is the master clock the codec needs to run; BCLK and LRCLK are the bit and word-select clocks; TX sends audio to the shield’s DAC, and RX receives audio from the shield’s ADC.
I²C (control bus) — pins 18/19 let the Teensy configure the SGTL5000 (volume, sample rate, input routing, etc.) via the AudioControlSGTL5000 object in the Teensy Audio Library.
3.3V — the SGTL5000 runs on 3.3V. The Teensy 4.0’s 3V3 pin can supply it directly. Don’t connect the shield’s power to 5V — the codec is not 5V tolerant.
If you’re using the Teensy Audio Library, the AudioMemory() call and AudioControlSGTL5000 object handle all the I²C setup automatically once the wiring matches these pins.