User Manual

Arduino SPIWIFI_RESET or 38 )

For advanced use or reprogramming, we also connect the main RX/TX UART to the ESP32 - on Arduino that's

Serial2 and in CircuitPython use board.ESP_RX and board.ESP_TX . This is a unique/unshared Serial port that

is not the same as the RX/TX pins on the Metro breakout pins.

You can also connect to the ESP32 RTS pin (used in some serial contexts) on board.ESP_RTS or Arduino 34 .

The ESP32 GPIO0 pin for bootloader enable is connected to board.ESP_GPIO0 or Arduino ESP32_GPIO0 or 35

Logic pins

This is the general purpose I/O pin set for the microcontroller.

All logic is 3.3V

All of the pins except SCL can do PWM output (A0 has true analog output instead)

All pins can be interrupt inputs

Top Row

#0 / RX - GPIO #0, also receive (input) pin for Serial1 (hardware UART)

#1 / TX - GPIO #1, also transmit (output) pin for Serial1

#2 through #12 - These are general purpose GPIO

#13 - GPIO #13 and is connected to the red LED marked L next to the USB jack.

SDA - the I2C (Wire) data pin. There's a 10K pull up on this pin to 3V already installed

SCL - the I2C (Wire) clock pin. There's a 10K pull up on this pin to 3V already installed

Bottom Row

A0 - This pin is analog

input

A0 but is also an analog

output

due to having a DAC (digital-to-analog converter).

This is the first DAC, and is 'independent' of A1. You can set the raw voltage to anything from 0 to 3.3V, unlike

PWM outputs this is a true analog output

A1 - This pin is analog

input

A1 but is also an analog

output

due to having a DAC (digital-to-analog converter).

This is the second DAC, and is 'independent' of A0. You can set the raw voltage to anything from 0 to 3.3V,

unlike PWM outputs this is a true analog output