No
No
N/A
Espressif ESP32-LyraT
Audio development board with codec, mic, and speaker support - designed for voice assistant applications.
ESP32
MCU
240MHz
clock
4MB
flash
520KB
SRAM
13· 8 ADC
GPIO
BLE 4.2+ WiFi
radio
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 involvementLRCKIO25DSDINIO26SCLIO23SDAIO18
Freely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| MCLK | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | Strapping |
| SCLK | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| ASDOUT | GPIO35 | Cannot be used as output; only suitable for input. | Other |
| MTDO | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| MTCK | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| MTDI | MTDI (GPIO12) | Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used. | Strapping |
| MTMS | MTMS (GPIO14) | Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot. | Other |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| TX | U0TXD (GPIO1) | Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console. | USB |
| RX | U0RXD (GPIO3) | Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads. | USB |
These are recommendations, not hard rules - with the right pull-ups, timing and boot-state awareness most pins can be made to work. When in doubt, start green.
Pinout notes 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…
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. 7 of the exposed pins carry boot-time or system duties on the ESP32 (MCLK, SCLK, ASDOUT and 4 more).
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Serial chip: CP2102N. Not detected? Hold BOOT while plugging in.
2
Flash with your tool
Arduino IDE, PlatformIO, ESPHome or esptool - copy the settings on the right.
3
Verify it runs
The blink example uses GPIO25 - swap for your board's LED pin if different.
Board: Esp32 Lyrat
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(25, OUTPUT);
digitalWrite(25, LOW); // on (often inverted)[env:esp32-lyrat]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: esp32_lyrat
framework:
type: esp-idf
# blink - GPIO25
output:
- platform: gpio
pin: 25
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesptool.py --chip esp32 --port /dev/ttyACM0 \
write_flash 0x0 firmware.binBuild details: sketch space 1966080 B · data 327680 B · DIO
Specifications
ESP32Compute
MCU
ESP32
Clock
240 MHz
SRAM · Flash
520 KB · 4MB · 8MB (QSPI) PSRAM
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
4.2 LE
Antenna
PCB
I/O
GPIO · ADC
13 · 8
UART · I²C · SPI
3 · 2 · 4
PWM
16 channels
Power
USB
Micro-USB
Serial
CP2102N
Boot address
0x1000
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
1.88 MB · 320 KB
The Espressif ESP32-LyraT uses esptool_py for firmware uploads, esp_ota for over-the-air (OTA) updates. Flash mode is DIO with DIO boot mode. The maximum sketch size is 1.88 MB with 320 KB available for data.
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
Board datasheet docs.espressif.com↗ ESP32 datasheet espressif.com↗ ESP32-LyraT V4.3 Hardware Reference (ESP-ADF) docs.espressif.com↗ESP32-LyraT V4.3 Schematic (PDF) dl.espressif.com↗ESP-ADF audio_board lyrat_v4_3 board_pins_config.c (I2S/I2C GPIO map) github.com↗ESP-ADF audio_board lyrat_v4_3 board_def.h (SD/PA/LED/key GPIO defines) github.com↗
Similar boards
