Espressif ESP32-LyraT
Audio development board with codec, mic, and speaker support - designed for voice assistant applications.
Espressif ESP32-LyraT Pinout
17 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | - | 3V33.3V | power | - | UART Header JP2 pin 1; 3.3V rail |
| 2 | 1 | TXIO1TXD0 | uart | uart | UART Header JP2 pin 2; UART0 TX to CP2102N USB-UART bridge |
| 3 | 3 | RXIO3RXD0 | uart | uart | UART Header JP2 pin 3; UART0 RX from CP2102N USB-UART bridge |
| 4 | - | GND | ground | - | UART Header JP2 pin 4; ground |
| 5 | 0 | MCLKIO0 | strapping | adc · touch | I2S Header JP4 pin 1; ES8388 I2S master clock. Strapping/boot pin (also automatic-upload IO0) |
| 6 | 5 | SCLKIO5 | strapping | - | I2S Header JP4 pin 2; ES8388 I2S bit clock (BCK). Strapping pin |
| 7 | 25 | LRCKIO25DAC1 | safe | adc · dac | I2S Header JP4 pin 3; ES8388 I2S word/LR clock (WS) |
| 8 | 26 | DSDINIO26DAC2 | safe | adc · dac | I2S Header JP4 pin 4; I2S data ESP32 to codec (SDOUT) |
| 9 | 35 | ASDOUTIO35 | strapping | adc | I2S Header JP4 pin 5; I2S data codec to ESP32 (SDIN). Input-only GPIO |
| 10 | - | GND | ground | - | I2S Header JP4 GND |
| 11 | 23 | SCLIO23 | safe | - | I2C Header JP5 pin 1; ES8388 control clock (shared I2C SCL) |
| 12 | 18 | SDAIO18 | safe | - | I2C Header JP5 pin 2; ES8388 control data (shared I2C SDA) |
| 13 | - | GND | ground | - | I2C Header JP5 GND |
| 14 | 15 | MTDOIO15TDO | strapping | adc · touch | JTAG Header JP7 pin 1 (TDO); shared with MicroSD CMD |
| 15 | 13 | MTCKIO13TCK | strapping | adc · touch | JTAG Header JP7 pin 2 (TCK); shared with MicroSD D3 and touch key Vol- (T4) |
| 16 | 12 | MTDIIO12TDI | strapping | adc · touch | JTAG Header JP7 pin 3 (TDI); shared with MicroSD D2 and AUX-in detect. Strapping pin |
| 17 | 14 | MTMSIO14TMS | strapping | adc · touch | JTAG Header JP7 pin 4 (TMS); shared with MicroSD CLK |
Start with these
4 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
9 pins · 9 things to knowTXGPIO1 Default UART0 TX pin for USB-serial programming and console. UART
Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console.
RXGPIO3 Default UART0 RX pin for USB-serial programming (console input). UART
Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads.
MCLKGPIO0 Bootstrapping pin (enter bootloader when low); internal pull-up. Strapping
Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.
SCLKGPIO5 Bootstrapping pin; internal pull-up; VSPI CS0 (default SPI chip-select); acts as FSPIWP (flash write-protect) on internal-flash variants. Strapping
Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.
ASDOUTGPIO35 Input-only GPIO (no output driver); ADC1 channel 7. Other
Cannot be used as output; only suitable for input.
MTDOGPIO15 Bootstrapping pin; JTAG TDO; controls UART0 boot log output; also HSPICS0 (secondary SPI CS). Strapping
Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.
MTCKGPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
MTDIGPIO12 Bootstrapping pin; JTAG TDI; sets flash voltage (VDD_SDIO); also HSPIQ (flash data line). Strapping
Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used.
MTMSGPIO14 JTAG mode select pin (TMS); also HSPI CLK and PWM-capable GPIO. JTAG
Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.
The Espressif ESP32-LyraT pinout brings out 17 pins - 13 usable GPIO alongside the 3V3 and GND power rails.
For peripherals, I²C is mapped to SDA on GPIO18 and SCL on GPIO23, while TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
On the analog side there are 8 ADC-capable pins for sensors and battery monitoring, 5 capacitive-touch inputs and 2 true DAC outputs.
If you want zero surprises, LRCK, DSDIN, SCL and SDA are free of any such role - the safest first picks. 9 of the exposed pins carry boot-time or system duties on the ESP32 (TX, RX, MCLK and 6 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 Wrover Module Flash Size: 4MB (32Mb) Flash Mode: DIO PSRAM: QSPI PSRAM Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO25 - wire an LED and resistor to it
void setup() {
pinMode(25, OUTPUT);
}
void loop() {
digitalWrite(25, HIGH); delay(500);
digitalWrite(25, LOW); delay(500);
}[env:esp32-lyrat]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600
board_build.arduino.memory_type = qio_qspi
build_flags = -DBOARD_HAS_PSRAMesp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
psram:
mode: quad
speed: 80MHz
# blink - GPIO25
output:
- platform: gpio
pin: 25
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32dev (same ids as PlatformIO).esptool.py --chip esp32 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32 · vs other ESP32 chips →About this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $20.00 - in line with other ESP32 boards.
Only 13 GPIO are broken out, where most ESP32 boards manage about 24 - worth checking the pinout covers what you need.
Onboard you'll find 8MB (QSPI) PSRAM, a microSD slot, a microphone (Dual mic), a speaker connector, an audio codec (ES8388), an amplifier (NS4150), battery charging, status LEDs (Standby, Charging) and Boot/Reset/Play/Set/Vol+/Vol- buttons.
The ESP32-LyraT is a development board designed for audio applications. It features an ESP32-WROVER module with Wi-Fi and Bluetooth connectivity, an onboard audio codec (ES8388), and an SD card slot. The board supports AEC, noise reduction, and voice recognition, making it ideal for smart audio projects such as voice assistants, smart speakers, and audio streaming applications.
- 3.5mm headphone jack with insertion detection
- 3.5mm auxiliary (AUX) stereo input
- Stereo 3 W speaker outputs (two NS4150 Class-D amps)
Where to buy
prices are typical street pricesResources
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