ESP32 Bench
Boards: ESP32, S3, C3
Flash and monitor: Web Serial

Boards

Header layouts follow Espressif's user guides. The tested pins and field notes come from ProbeHarbor's hardware test log, where each board was flashed and run with real sensors.

ESP32-DevKitC V4, 38 pin. USB connector at the bottom.

ESP32-DevKitC V4, 38 pin

Arduino: ESP32 Dev Module21 projects

Pins tested on hardware

I2CSDA 21 / SCL 22
One-wire or DHT dataGPIO 4
BOOT buttonGPIO 0

Field notes

  • GPIO 34, 35, VP (36) and VN (39) are input only and have no pull-ups.
  • GPIO 0, 2, 12 and 15 are strapping pins. Keep loads off them at boot.
  • D0 to D3, CMD and CLK are wired to the flash chip. Leave them unconnected.
  • The DevKitC V4 has no user LED. Many 30-pin clones put one on GPIO 2.
Buy ESP32 DevKit at AmazonEspressif user guide
ESP32-S3-DevKitC-1, 44 pin. USB connector at the bottom.

ESP32-S3-DevKitC-1, 44 pin

Arduino: ESP32S3 Dev Module11 projects

Pins tested on hardware

I2CSDA 8 / SCL 9
One-wire or DHT dataGPIO 4
BOOT buttonGPIO 0

Field notes

  • The board has two USB ports: a UART bridge and the chip's native USB on GPIO 19 and 20.
  • Opening the native USB port resets the board, so every new serial connection restarts your firmware.
  • Firmware that should talk on either port has to listen on both. ProbeHarbor's probe ignored settings on the native port until it did.
  • The RGB LED is on GPIO 38 on v1.1 boards and GPIO 48 on the first revision.
  • ProbeHarbor builds for 4 MB flash so modules smaller than the DevKitC's default 8 MB still boot.
Buy ESP32-S3-DevKitC-1 at AdafruitEspressif user guide
ESP32-C3-DevKitM-1, 30 pin. USB connector at the bottom.

ESP32-C3-DevKitM-1, 30 pin

Arduino: ESP32C3 Dev Module10 projects

Pins tested on hardware

I2CSDA 6 / SCL 7
One-wire or DHT dataGPIO 4
BOOT buttonGPIO 9

Field notes

  • Native USB serial is off by default on the DevKitM-1 build. Without -DARDUINO_USB_MODE=1 a board connected only by its native port boots but prints nothing.
  • GPIO 9 is the BOOT button and GPIO 8 drives the RGB LED.
  • GPIO 18 and 19 are the native USB data lines.
  • Check the silkscreen before wiring: a sensor on the wrong pad was the one wiring fault in ProbeHarbor's C3 test.
Buy ESP32-C3-DevKitM-1 at AdafruitEspressif user guide

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