HiLetgo ESP-WROOM-32 Development Board
ESP32 development board with 2.4GHz WiFi, Bluetooth, dual cores, and Arduino IDE compatibility.
HiLetgo ESP-WROOM-32 Development Board Pinout
33 pins
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 36 | IO36GPIO36 | strapping | adc | ADC1_CH0, GPIO36 |
| 2 | 39 | IO39GPIO39 | strapping | adc | ADC1_CH3, GPIO39 |
| 3 | 34 | IO34GPIO34 | strapping | adc | ADC1_CH6, GPIO34 |
| 4 | 35 | IO35GPIO35 | strapping | adc | ADC1_CH7, GPIO35 |
| 5 | 32 | IO32GPIO32 | safe | adc | ADC1_CH4, GPIO32 |
| 6 | 33 | IO33GPIO33 | safe | adc | ADC1_CH5, GPIO33 |
| 7 | 25 | IO25GPIO25 | safe | adc · dac | DAC1, ADC2_CH8, GPIO25 |
| 8 | 26 | IO26GPIO26 | safe | adc · dac | DAC2, ADC2_CH9, GPIO26 |
| 9 | 27 | IO27GPIO27 | safe | adc | ADC2_CH7, GPIO27 |
| 10 | 14 | IO14GPIO14 | strapping | adc | ADC2_CH6, GPIO14 |
| 11 | 12 | IO12GPIO12 | strapping | adc | ADC2_CH5, GPIO12 |
| 12 | - | GND | ground | - | Ground |
| 13 | 13 | IO13GPIO13 | strapping | adc | ADC2_CH4, GPIO13 |
| 14 | 9 | IO9GPIO9 | strapping | - | SD_DATA2, GPIO9 |
| 15 | 10 | IO10GPIO10 | strapping | - | SD_DATA3, GPIO10 |
| 16 | 11 | IO11GPIO11 | strapping | - | SD_CMD, GPIO11 |
| 17 | 6 | IO6GPIO6 | strapping | - | SD_CLK, GPIO6 |
| 18 | 7 | IO7GPIO7 | strapping | - | SD_DATA0, GPIO7 |
| 19 | 8 | IO8GPIO8 | strapping | - | SD_DATA1, GPIO8 |
| 20 | 15 | IO15GPIO15 | strapping | adc | ADC2_CH3, GPIO15 |
| 21 | 2 | IO2GPIO2 | strapping | adc | ADC2_CH2, GPIO2, LED |
| 22 | 0 | IO0GPIO0 | strapping | adc | ADC2_CH1, GPIO0, BOOT |
| 23 | 4 | IO4GPIO4 | safe | adc | ADC2_CH0, GPIO4 |
| 24 | 16 | IO16GPIO16 | safe | - | GPIO16 |
| 25 | 17 | IO17GPIO17 | safe | - | GPIO17 |
| 26 | 5 | IO5GPIO5 | strapping | - | GPIO5 |
| 27 | 18 | IO18GPIO18 | safe | - | GPIO18 |
| 28 | 19 | IO19GPIO19 | safe | - | GPIO19 |
| 29 | 21 | IO21GPIO21 | safe | - | GPIO21 |
| 30 | 3 | RXGPIO3 | uart | uart | UART0 Receive |
| 31 | 1 | TXGPIO1 | uart | uart | UART0 Transmit |
| 32 | 22 | IO22GPIO22 | safe | - | GPIO22 |
| 33 | 23 | IO23GPIO23 | safe | - | GPIO23 |
Start with these
13 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
13 pins · 12 things to knowIO36 Input-only GPIO (no output); ADC1 channel 0, Hall sensor VP. Other
Cannot be used as output; only suitable for input (e.g., analog read).
IO39IO35 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- IO39Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN.
- IO35Input-only GPIO (no output driver); ADC1 channel 7.
IO34 Input-only GPIO (no output driver); ADC1 channel 6. Other
Cannot be used as output (no drive capability); only suitable for analog/digital input.
IO14 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.
IO12 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.
IO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
IO15 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.
IO2 Bootstrapping pin (must be low or floating at reset); internal pull-down. Strapping
If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.
IO0 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.
IO5 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.
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.
TXGPIO1 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.
Only if you know the tricks
6 pins · 4 things to knowIO9IO10 SPI flash/PSRAM data lines SD2 and SD3 (flash HOLD and WP) Flash
Used by internal flash/PSRAM; typically not exposed on modules, avoid using as GPIO.
- IO9Connected to SPI flash/PSRAM data 2 (SD2, flash HOLD).
- IO10Connected to SPI flash/PSRAM data 3 (SD3, flash WP).
IO11 Connected to SPI flash command/CS (CMD/CS0). Flash
Used by internal flash (chip select/command); not available for general use.
IO6 Connected to SPI flash clock (SCK/CLK). Flash
Used for internal flash/PSRAM communication; not available for general GPIO.
IO7IO8 SPI flash data lines SD0 and SD1 Flash
Used for internal flash/PSRAM data; not available for general GPIO.
- IO7Connected to SPI flash data 0 (SD0).
- IO8Connected to SPI flash data 1 (SD1).
The HiLetgo ESP-WROOM-32 Development Board breaks out 33 pins in total: 32 GPIO for your project, with GND handling power.
For peripherals, TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
On the analog side there are 16 ADC-capable pins for sensors and battery monitoring and 2 true DAC outputs.
If you want zero surprises, IO32, IO33, IO25, IO26 and 9 more are free of any such role - the safest first picks. 13 of the exposed pins carry boot-time or system duties on the ESP32 (IO36, IO39, IO34 and 10 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 Dev Module Flash Size: 4MB (32Mb) Flash Mode: DIO Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO32 - wire an LED and resistor to it
void setup() {
pinMode(32, OUTPUT);
}
void loop() {
digitalWrite(32, HIGH); delay(500);
digitalWrite(32, LOW); delay(500);
}[env:hiletgo-esp-wroom-32]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
# blink - GPIO32
output:
- platform: gpio
pin: 32
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).Good to know
board-specific quirks worth 60 secondsHiLetgo ESP-WROOM-32 Compatibility Arduino IDE Setup Board Selection: Use "Node32" for Bluetooth functionality, or "ESP32 Dev Module" for standard operation Built-in LED: Connected to GPIO2 - use digitalWrite(2, HIGH) to control Upload Speed: Supports high-speed uploads up to 921,600 baud Technical Specifications Based on ESP32-WROOM-32 module with TSMC 40nm ultra-low power technology. Supports AP, STA, and AP+STA…
HiLetgo ESP-WROOM-32 Compatibility
Arduino IDE Setup
- Board Selection: Use "Node32" for Bluetooth functionality, or "ESP32 Dev Module" for standard operation
- Built-in LED: Connected to GPIO2 - use
digitalWrite(2, HIGH)to control - Upload Speed: Supports high-speed uploads up to 921,600 baud
Technical Specifications
Based on ESP32-WROOM-32 module with TSMC 40nm ultra-low power technology. Supports AP, STA, and AP+STA modes for WiFi connectivity.
Getting Started
Connect via Micro-USB, install ESP32 board support in Arduino IDE, and start developing IoT applications with built-in WiFi and Bluetooth capabilities.
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 $8.99 - less than the ~$20 most ESP32 boards go for.
32 GPIO are broken out - more than most ESP32 boards, so the pin budget is rarely the constraint.
Onboard you'll find EN/Boot buttons.
Where to buy
prices are typical street pricesResources
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