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Power Pins

  • 3V3 –> Provides a 3.3V voltage and up to 1A current output capacity via a DC-DC step-down converter. Output is available when either USB or Li-Po battery power input is connected. It can be used to power externally connected units.
  • VBAT (BAT) –> Used to connect the power input (V+) terminal of a single-cell Li-Po battery. When powered via the Li-Po battery connector, it can also be used to provide a power output in the range of 3.3V–4.2V.
  • GND –> The common ground line of the circuit for all power and logic connection pins.

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Logic Pins (Input/Output Pins)

  • All pins can be used as digital input/output pins. Logic “0” corresponds to 0V, and logic “1” corresponds to 3.3V. There are a total of 13 pins. The pins are not 5V tolerant.

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Analog Pins

  • A0, A1, SCL, A2, A3, and A4 pins are used as input pins for analog signals. There are a total of 6 pins.

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Communication Pins

  • TX – RX –> Serial communication (UART) pins. Firmware uploading and terminal communication are performed via these pins. TX is the output pin and RX is the input pin. Besides UART communication, they can also be used as digital input/output pins. They are also referred to as D1 (TX) and D0 (RX).
  • I2C –> Sensors or actuators can be controlled via the SDA and SCL pins. SDA (both input and output) is the data line, while SCL (output) is the clock (timing) synchronization pin. These pins are held at logic “1” (3.3V) by 10K pull-up resistors. Apart from I2C communication, they can also be used as digital input/output pins. They are also connected to D4 (SDA) and D6 (SCL) pins.
  • SPI –> Sensors or actuators can be controlled via MOSI, MISO, SCLK, and SS* pins. MOSI (output) is the data pin, MISO (input) is the data pin, SCLK (output) is the clock (timing) synchronization pin, and SS is the slave select pin. These pins can also be used as digital input/output pins. They are also referred to as SS (D5), SCLK (A3), MISO (A4), and MOSI (A5). All digital pins can be used for SPI communication.
  • I2S, TWAI, and IR (Infrared Remote Control) –> All digital pins can be used.

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PWM Pins

  • All digital pins can be used as Pulse Width Modulation (PWM) square wave output pins. They are also referred to as A0 (PWM0), A1 (PWM1), and A2 (PWM2).

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JTAG Pins

  • A3, A4, A5, and D5 pins can be used to perform MTMS, MTDI, MTCK, and MTDO functions, respectively.

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RGB Pin

  • RGBLED –> The pin to which the onboard addressable RGB LED is connected. It is not routed externally via pins. It is also referred to as D3.

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Button Pin

  • GPKEY –> The pin connected to the onboard general-purpose button. It is also used to put the system into manual upload mode. It is held at logic “1” (3.3V) with a 10K pull-up resistor. It is also connected to the D2 pin and can be used as a digital input/output pin.

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Programming Pins

  • CHIP_EN –> To enable operation of the ESP32-C3 microcontroller, this pin must be held at logic “1” (3.3V). This is ensured by an internally placed pull-up resistor. The “RES” button is connected to this pin and is used to reset the system. When the button is pressed, the CHIP_EN pin is pulled to logic “0” (0V).
  • BOOT –> Used to put the system into manual upload mode. It is the pin connected to the onboard general-purpose button (BUT). It is held at logic “1” (3.3V) with a 10K pull-up resistor. It is also connected to the D2 pin.