OLIMEX ESP32-GATEWAY
ESP32 dev board with 100 Mbit Ethernet and a microSD slot - built for wired IoT gateway projects.
OLIMEX ESP32-GATEWAY Pinout
13 pins · 2.54 mm pitch
| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 1 | TXPWM | uart | uart | |
| 2 | 3 | RXPWM | uart | uart | |
| 3 | 5 | ETH_PHY_POWERSSPWM | strapping | spi | |
| 4 | 16 | SCLPWM | safe | i2c | |
| 5 | 18 | SCKPWM | safe | spi | |
| 6 | 19 | MISOPWM | safe | spi | |
| 7 | 23 | MOSIPWM | safe | spi | |
| 8 | 32 | SDAA4T9PWM | safe | adc · touch · i2c | |
| 9 | 33 | LED_BUILTINPWM | safe | - | |
| 10 | 34 | KEY_BUILTIN | strapping | - | |
| 11 | 35 | A7 | strapping | adc | |
| 12 | 36 | A0 | strapping | adc | |
| 13 | 39 | A3 | strapping | adc |
Start with these
6 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
7 pins · 6 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.
ETH_PHY_POWERGPIO5 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.
KEY_BUILTINGPIO34 Input-only GPIO (no output driver); ADC1 channel 6. Other
Cannot be used as output (no drive capability); only suitable for analog/digital input.
A7GPIO35A3GPIO39 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- A7Input-only GPIO (no output driver); ADC1 channel 7.
- A3Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN.
A0GPIO36 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).
The OLIMEX ESP32-GATEWAY pinout brings out 13 GPIO pins at a 2.54 mm pitch - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO32 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.
On the analog side there are 4 ADC-capable pins for sensors and battery monitoring and 1 capacitive-touch inputs.
If you want zero surprises, SCL, SCK, MISO, MOSI and 2 more are free of any such role - the safest first picks. 7 of the exposed pins carry boot-time or system duties on the ESP32 (TX, RX, ETH_PHY_POWER and 4 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 GPIO16 - wire an LED and resistor to it
void setup() {
pinMode(16, OUTPUT);
}
void loop() {
digitalWrite(16, HIGH); delay(500);
digitalWrite(16, LOW); delay(500);
}[env:esp32-gateway]
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 - GPIO16
output:
- platform: gpio
pin: 16
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 · 62 × 50 mm · vs other ESP32 chips →Dimensions
About this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $19.74 - 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 a microSD slot, wired Ethernet (LAN8710A), status LEDs (Power, User) and Reset/User buttons.
- Optional external antenna variant (-EA) uses ESP32-WROOM-32UE with u.FL connector
- Industrial-grade variant (-IND) rated -40 to +85C
Where to buy
prices are typical street pricesResources
Similar boards
