ESP32-C Series GPIO Reference
ESP32-C Series GPIO Reference
The ESP32-C Series includes the ESP32-C2, ESP32-C3, ESP32-C5, and ESP32-C6 processors. Unlike the Original ESP32 and ESP32-S Series, the C Series is based on the RISC-V processor architecture and is designed to provide lower cost, lower power consumption, and modern wireless capabilities.
GPIO assignments vary between the different C Series processors and development boards. This page summarizes the common GPIO characteristics of the ESP32-C Series and provides guidance for DIY holiday lighting applications.
GPIO Summary
| Processor | Approximate GPIO | Input | Output | USB | Wireless | Notes |
|---|---|---|---|---|---|---|
| ESP32-C2 | Up to 21 | Yes | Yes | Native USB (selected modules) | Wi-Fi + Bluetooth LE | Entry-level RISC-V processor. |
| ESP32-C3 | Up to 22 | Yes | Yes | Native USB | Wi-Fi + Bluetooth LE | Most common C Series processor. |
| ESP32-C5 | Up to 30 | Yes | Yes | Native USB | Wi-Fi 6 + Bluetooth LE | Expanded GPIO and newer wireless features. |
| ESP32-C6 | Up to 30 | Yes | Yes | Native USB | Wi-Fi 6 + Bluetooth LE + IEEE 802.15.4 | Supports Thread and Zigbee. |
GPIO Categories
Recommended for Pixel Outputs
Most GPIO pins capable of digital output may be used for pixel data provided they are not reserved by the processor, development board, or firmware.
Boot (Strapping) Pins
Several GPIO pins are sampled during reset to determine processor startup mode. Refer to the processor datasheet and development board documentation before assigning these pins.
Reserved Pins
Certain GPIO pins may be dedicated to flash memory, USB functions, debugging interfaces, or other onboard hardware depending on the module or development board.
USB Pins
Most ESP32-C Series processors include native USB support. GPIO pins assigned to USB should generally not be reassigned unless USB communication is not required.
Processor Notes
ESP32-C2
- Entry-level RISC-V processor
- Low-cost solution
- Wi-Fi and Bluetooth LE
- Suitable for simple controllers
ESP32-C3
- Most widely used C Series processor
- Native USB
- Excellent WLED compatibility
- Low power consumption
- Popular for compact pixel controllers
ESP32-C5
- Wi-Fi 6 support
- Additional GPIO capability
- Improved wireless performance
- Limited community adoption at present
ESP32-C6
- Wi-Fi 6
- Bluetooth LE
- IEEE 802.15.4
- Supports Thread and Zigbee
- Well suited for future smart lighting applications
Practical Notes
Although the processor may support a particular GPIO, the development board may not expose every pin.
Some GPIO pins may already be connected to:
- USB interface
- Status LEDs
- Boot and reset buttons
- RGB LEDs
- Flash memory
- Battery monitoring circuits
- Sensors
- Displays
Always consult the development board schematic before assigning GPIO pins.
Community Verified GPIO
The following information has been verified through testing by members of the DIY holiday lighting community.
| Development Board | Processor | Firmware | Version | Verified Pixel Outputs | Verified By | Notes |
|---|---|---|---|---|---|---|
| No community testing submitted yet. |
Additional community testing is encouraged.
Firmware Considerations
Firmware may impose additional GPIO restrictions beyond those defined by the processor or development board.
Always verify GPIO support for the firmware version being used.
See: