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WT32-ETH01 Ethernet Module
ESP32-based Ethernet module with LAN port - ideal for wired IoT applications and secure local networks.
60 × 26 mm
ESP32
MCU
240MHz
clock
4MB
flash
520KB
SRAM
15· Two 12-bit, 18 Channels ADC
GPIO
BLE 4.2+ WiFi
radio
Pinout
28 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | - | EN | control | - | Chip enable (active high) |
| 2 | - | GND | ground | - | |
| 3 | - | 3V3 | power | - | |
| 4 | - | EN | control | - | Chip enable (active high) |
| 5 | 32 | CFGIO32 | safe | pwm | |
| 6 | 33 | 485_ENIO33 | safe | pwm | |
| 7 | 5 | RXDIO5 | strapping | uart · pwm | |
| 8 | 17 | TXDIO17 | strapping | uart · pwm | |
| 9 | - | GND | ground | - | |
| 10 | - | 3V3 | power | - | |
| 11 | - | GND | ground | - | |
| 12 | - | 5V | power | - | |
| 13 | - | LINK | safe | - | Ethernet link/activity LED |
| 14 | - | NC | safe | - | |
| 15 | 1 | TXDIO1 | uart | uart · pwm | |
| 16 | 3 | RXDIO3 | uart | uart · pwm | |
| 17 | 0 | IO0 | strapping | pwm | |
| 18 | - | GND | ground | - | |
| 19 | 39 | IO39 | strapping | - | Input only |
| 20 | 36 | IO36 | strapping | - | Input only |
| 21 | 15 | IO15 | strapping | pwm | |
| 22 | 14 | IO14 | strapping | pwm | |
| 23 | 12 | IO12 | strapping | pwm | |
| 24 | 35 | IO35 | strapping | - | Input only |
| 25 | 4 | IO4 | strapping | pwm | |
| 26 | 2 | IO2 | strapping | pwm | |
| 27 | - | GND | ground | - | |
| 28 | - | NC | safe | - |
Start with these
2 pins with no boot or system involvementCFGIO32485_ENIO33
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 |
|---|---|---|---|
| RXD | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| IO0 | GPIO0 | Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode. | Strapping |
| IO39 | GPIO39 (SENSOR_VN) | Cannot be used as output; only suitable for input. | Other |
| IO36 | GPIO36 (SENSOR_VP) | Cannot be used as output; only suitable for input (e.g., analog read). | Other |
| IO15 | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| IO14 | MTMS (GPIO14) | Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot. | Other |
| IO12 | 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 |
| IO35 | GPIO35 | Cannot be used as output; only suitable for input. | Other |
| IO4 | GPIO4 | Sampled at reset for boot config; should not be driven at boot (affects boot mode timing). | Strapping |
| IO2 | GPIO2 | If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure. | Strapping |
Only if you know the tricks
wired to flash or USB - expect a fight| Pin | Label | What to know | Role |
|---|---|---|---|
| TXD | GPIO17 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
| TXD | 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 |
| RXD | 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 Across 28 pins (2.54 mm pitch), the WT32-ETH01 Ethernet Module exposes 15 GPIO plus GND , 3V3 and 5V for power. Beyond plain digital I/O you get PWM on 12…
Across 28 pins (2.54 mm pitch), the WT32-ETH01 Ethernet Module exposes 15 GPIO plus GND, 3V3 and 5V for power.
Beyond plain digital I/O you get PWM on 12 pins.
10 of the exposed pins carry boot-time or system duties on the ESP32 (RXD, IO0, IO39 and 7 more) - check the guidance above before wiring anything to them. CFG and 485_EN are free of any such role - the safest first picks.
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Serial chip: onboard. 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 GPIO32 - swap for your board's LED pin if different.
Board: Wt32 Eth01
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(32, OUTPUT);
digitalWrite(32, LOW); // on (often inverted)[env:wt32-eth01]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: wt32-eth01
framework:
type: esp-idf
# blink - GPIO32
output:
- platform: gpio
pin: 32
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 1310720 B · data 327680 B · DIO
Specifications
ESP32 · 60 × 26 mmCompute
MCU
ESP32
Clock
240 MHz
SRAM · Flash
520 KB · 4MB
Radio
Wi-Fi
802.11 b/g/n
Bluetooth
4.2 LE
Antenna
PCB
I/O
GPIO · ADC
15 · Two 12-bit, 18 Channels
UART · I²C · SPI
3 · 2 · 4
PWM
16 channels
Power
USB
None
Serial
-
Boot address
0x1000
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
1.25 MB · 320 KB
60 × 26 mm · pin pitch 2.54 mm
The WT32-ETH01 Ethernet Module 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 1.25 MB with 320 KB available for data.
About this board
Inside sits the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
At $9.00 it's cheaper than most ESP32 boards, which usually run around $20.
Only 15 GPIO are broken out, where most ESP32 boards manage about 24 - worth checking the pinout covers what you need.
Around the module: wired Ethernet (LAN8720).
Where to buy
prices are typical street pricesWT32-ETH01 Ethernet Module
$9.00per unit, typical
Resources
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