No
No
N/A
OLIMEX ESP32-PoE
ESP32 board with PoE support - ideal for networked, powered-over-Ethernet applications.
80 × 28 mm
ESP32
MCU
240MHz
clock
4MB
flash
520KB
SRAM
12· Two 12-bit, 18 Channels ADC
GPIO
BLE 4.2+ WiFi
radio
Pinout
12 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | TXPWM | uart | uart | |
| 2 | 2 | MOSIPWM | strapping | spi | |
| 3 | 3 | RXPWM | uart | uart | |
| 4 | 4 | TX1PWM | strapping | - | |
| 5 | 5 | SSPWM | strapping | spi | |
| 6 | 12 | ETH_PHY_POWERPWM | strapping | - | |
| 7 | 13 | SDAPWM | strapping | i2c | |
| 8 | 14 | SCKPWM | strapping | spi | |
| 9 | 15 | MISOPWM | strapping | spi | |
| 10 | 16 | SCLPWM | strapping | i2c | |
| 11 | 34 | KEY_BUILTIN | strapping | - | |
| 12 | 36 | RX1 | strapping | - |
Fine - with a little care
sampled at boot or shared with debug/serial| Pin | Label | What to know | Role |
|---|---|---|---|
| MOSI | GPIO2 | If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure. | Strapping |
| TX1 | GPIO4 | Sampled at reset for boot config; should not be driven at boot (affects boot mode timing). | Strapping |
| SS | GPIO5 | Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot. | Strapping |
| ETH_PHY_POWER | 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 |
| SDA | MTCK (GPIO13) | Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed. | Other |
| SCK | MTMS (GPIO14) | Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot. | Other |
| MISO | MTDO (GPIO15) | Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change. | Strapping |
| KEY_BUILTIN | GPIO34 | Cannot be used as output (no drive capability); only suitable for analog/digital input. | Other |
| RX1 | GPIO36 (SENSOR_VP) | Cannot be used as output; only suitable for input (e.g., analog read). | 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 |
| SCL | GPIO16 | Connected to internal PSRAM on PSRAM-enabled modules; not usable as GPIO on those modules. | Flash |
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 OLIMEX ESP32-PoE pinout brings out 12 GPIO pins at a 2.54 mm pitch - every one of them usable in your project. For peripherals, I²C is mapped to SDA on…
The OLIMEX ESP32-PoE pinout brings out 12 GPIO pins at a 2.54 mm pitch - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO13 and SCL on GPIO16; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO1 and GPIO3 cover serial logging and flashing.
9 of the exposed pins carry boot-time or system duties on the ESP32 (MOSI, TX1, SS and 6 more).
Getting started
flash your first firmware in ~2 minutes1
Connect over USB
Serial chip: CH340T. 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 GPIO8 - swap for your board's LED pin if different.
Board: Esp32 Poe
Flash Size: 4MB · DIO
Upload Speed: 921600
// blink
pinMode(8, OUTPUT);
digitalWrite(8, LOW); // on (often inverted)[env:esp32-poe]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32:
board: esp32dev
variant: esp32-poe
framework:
type: esp-idf
# blink - GPIO8
output:
- platform: gpio
pin: 8
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 · 80 × 28 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
12 · Two 12-bit, 18 Channels
UART · I²C · SPI
3 · 2 · 4
PWM
16 channels
Power
USB
Micro-USB
Serial
CH340T
Boot address
0x1000
Flashing
Upload · OTA
esptool_py · esp_ota
Flash · Boot mode
DIO · DIO
Sketch · Data
1.25 MB · 320 KB
80 × 28 mm · pin pitch 2.54 mm
The OLIMEX ESP32-PoE 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
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $20.90 - in line with other ESP32 boards.
Only 12 GPIO are broken out, where most ESP32 boards manage about 24 - worth checking the pinout covers what you need.
Onboard you'll find a microSD slot, Power over Ethernet (PoE), wired Ethernet (LAN8710A), battery charging (BL4054B) via JST 2.0mm and Reset/User buttons.
- Non-isolated PoE - disconnect the Ethernet cable before USB programming (the ESP32-PoE-ISO variant adds galvanic isolation)
- IEEE 802.3af PoE handled by a TPS2375 (Si3402-B on older revisions)
- UEXT connector for I2C / SPI / UART module expansion
- EA variants replace the PCB antenna with an ESP32-WROOM-32UE module + u.FL external antenna
- LiPo connector uses reversed Olimex polarity - verify before plugging in a battery
- Deep-sleep consumption below 100µA
Where to buy
prices are typical street pricesOLIMEX ESP32-PoE
$20.90per unit, typical
Resources
Similar boards
