ESP32 Board Guide
Edit on GitHubChoosing and handling the ESP32 DevKit V1: variants, input-only pins, USB chips and board care
ESP32 Board Guide
Overview
The ESP32 DevKit V1 (30-pin) is the heart of the Aegis-Beacon. It provides the dual-core CPU, the USB programming interface and the onboard AMS1117-3.3 LDO that powers everything else.
Why This Board
| Requirement | How the DevKit V1 satisfies it |
|---|---|
| Dual-core CPU | Two Xtensa cores at 240 MHz |
| Two SPI-capable buses | VSPI for the radio, software SPI for the OLED |
| Native DAC | GPIO 25 (DAC1) for clean audio |
| 4 ADC-capable inputs | GPIO 34, 35 (buttons), 36 (battery ADC), 39 (radio DIO1) |
| Deep sleep | ~10 uA with RTC RAM retained |
| USB programming | Built-in CP2102/CH340 USB-serial |
30-Pin vs 38-Pin
Both work, but this project targets the 30-pin board:
| Feature | 30-pin | 38-pin |
|---|---|---|
| Breadboard friendly | Yes | Yes |
| Pins used by this project | All covered | Compatible |
| Onboard LDO | AMS1117-3.3 | AMS1117-3.3 |
The firmware and DATASHEET reference the 30-pin layout. If you have a 38-pin board, double-check every GPIO number against your physical pinout before wiring.
Input-Only Pins
Four pins on the ESP32 cannot be used as outputs and have no internal pull-up:
| GPIO | Use in this project |
|---|---|
| 34 | SW_DN (needs external 10k pull-up) |
| 35 | SW_UP (needs external 10k pull-up) |
| 36 | Battery ADC (SVP, input only) |
| 39 | TP4056 charging detect (SVN, input only) |
Warning
Never try to drive GPIO 34, 35, 36 or 39 as outputs. The firmware defines them as inputs; wiring them to a push-pull output will fight the device.
USB-Serial Chips
Boards ship with either a CP2102 or a CH340 chip:
| Chip | Driver | Notes |
|---|---|---|
| CP2102 | Silicon Labs VCP | Most common on name-brand boards |
| CH340 | CH340 driver | Common on cheap clones |
If the board does not enumerate on your PC, install the matching driver first, then try a data (not charge-only) USB cable.
Board Care
- Do not exceed 5.5 V on VBUS.
- The onboard LDO output is 3.3 V at up to 800 mA. The radio, OLED and GPS together stay within this budget.
- Keep the metal USB shield and antenna away from each other during RF tests.
- If the board gets hot to the touch, power it down immediately and check for a short on the 3.3 V rail.