Power

There are two ways you can power the Feather ESP32-S3, as well as other related pins.

• USB-C port - This is used for both powering and programming the board. You can power it with any USB C cable. When USB is plugged in it will charge the Lipoly battery.
• LiPoly connector/charger - You can plug in any 250mAh or larger 3.7/4.2V Lipoly battery into this JST 2-PH port to both power your Feather and charge the battery. The battery will charge from the USB power when USB is plugged in. If the battery is plugged in and USB is plugged in, the Feather will power itself from USB and it will charge the battery up.
• CHG LED - When the battery is charging, the yellow CHG LED will be lit. When charging is complete, the LED will turn off. If there's no battery plugged in, the CHD LED may blink rapidly - this is expected!
• GND - This is the common ground for all power and logic.
• BAT - This is the positive voltage to/from the 2-pin JST jack for the optional Lipoly battery.
• USB - This is the positive voltage to/from the USB C jack, if USB is connected.
• EN - This is the 3.3V regulator enable pin. It's pulled up, so connect to ground to disable the 3.3V regulator.
• 3.3V - These pins are the output from the 3.3V regulator, they can supply 500mA peak.

TFT Display

On the front of the board is a color 1.14" IPS TFT with 240x135 pixels. It's a bright and colorful display with ST7789 chipset that can be viewed at any angle.

There is a power pin that must be pulled high for the display to work. This is done automatically by CircuitPython and Arduino. The pin is available in CircuitPython and in Arduino as TFT_I2C_POWER.

ESP32-S3 WiFi Module

The ESP32-S3 is a highly-integrated, low-power, 2.4 GHz WiFi + BLE System-on-Chip (SoC) solution that has built-in native USB as well as some other interesting new technologies like Time of Flight distance measurements and AI acceleration.

The Feather ESP32-S3 has a dual-core 240 MHz chip, so it is comparable to ESP32's dual-core. However, there is no Bluetooth Classic support, only Bluetooth LE. This ESP32-S3 mini-module we are using on the Feather comes with 4 MB flash and 2 MB PSRAM, as well as 512KB of SRAM, so it's perfect for use with CircuitPython support or any time massive buffers are needed: for fast memory access use SRAM, for slower-but-roomier access use PSRAM.

MAX17048 Battery Monitor

The MAX17048 LiPoly Battery Monitor reports the voltage and charge percent over I2C. Connect it to your Lipoly or LiIon battery and it will let you know the voltage of the cell, and it does the annoying math of decoding the non-linear voltage to get you a valid percentage as well!

The battery monitor is available over I2C on address 0x36.

Logic Pins

These are the logic pins that can be used to connect FeatherWings, sensors, servos, LEDs and more!

No pins are shared, and no pins are 'special' bootstrapping pins, so you can use any of them for input, or output, with pullups or pulldowns, without worry.

ESP32 chips allow for 'multiplexing' of almost all signals so it isn't like some pins can do PWM and others can. You can connect any of the available PWM channels, I2S channels, UART, I2C or SPI ports to any pin. There are some exceptions....

There are six analog pins.

• A0 thru A5 can also be analog inputs. A0 thru A4 are on ADC2, and A5 is on ADC1.

The SPI pins are on the ESP32-S3 high-speed peripheral. You can set any pins to be the low-speed peripheral but you won't get the speedy interface!

• SCK - This is the SPI clock pin.
• MOSI - This is the SPI Microcontroller Out / Sensor In pin.
• MISO - This is the SPI Microcontroller In / Sensor Out pin.

The UART interface.

• RX - This is the UART receive pin. Connect to TX (transmit) pin on your sensor or breakout.
• TX - This is the UART transmit pin. Connect to RX (receive) pin on your sensor or breakout.

The I2C interface. This is shared by the STEMMA QT connector.

• SCL - This is the I2C clock pin. There is a 10k pullup on this pin.
• SDA - This is the I2C data pin. There is a 10k pullup on this pin.
  • In CircuitPython, you can use the STEMMA connector with board.SCL and board.SDA, or board.STEMMA_I2C().
  • There is an I2C power pin that needs to be pulled high for the TFT and the STEMMA QT connector to work properly. It is available in CircuitPython and Arduino as TFT_I2C_POWER. This pin is automatically pulled high in CircuitPython and Arduino.

The digital pins.

• D5-D6, D9-D13 - These are digital pins. D5, D6, D9 and D10 are on ADC1. D11-D13 are on ADC2.

Check the ESP32-S3 datasheet or the PrettyPins diagram above for the ADC channel names for each pin if you need them!

NeoPixel and Red LED

• NeoPixel LED - This addressable RGB NeoPixel LED, labeled Neo on the board, works both as a status LED (in CircuitPython and the bootloader), and can be controlled with code. It is available in CircuitPython as board.NEOPIXEL, and in Arduino as PIN_NEOPIXEL.
• There is a NeoPixel power pin that needs to be pulled high for the NeoPixel to work. This is done automatically in CircuitPython and Arduino. It is available in CircuitPython and Arduino as NEOPIXEL_POWER.
• Red LED - This little red LED, labeled #13 on the board, is on or blinks during certain operations (such as pulsing when in the bootloader), and is controllable in code. It is available in CircuitPython as board.LED, and in Arduino as LED_BUILTIN or 13.

STEMMA QT

This JST SH 4-pin STEMMA QT connector breaks out I2C (SCL, SDA, 3.3V, GND). It allows you to connect to various breakouts and sensors with STEMMA QT connectors or to other things using assorted associated accessories. It works great with any STEMMA QT or Qwiic sensor/device. You can also use it with Grove I2C devices thanks to this handy cable.

There is a power pin that must be pulled high for the STEMMA QT connector to work. This is done automatically in CircuitPython and Arduino. The pin is available in CircuitPython and in Arduino as TFT_I2C_POWER.

D1 and D2 Buttons

The D1 and D2 buttons are available for use as inputs in your code.

In CircuitPython, they are available as board.D1 and board.D2.

In Arduino, they are available as 1 and 2.

These two pins are pulled LOW by default, e.g. when not pressed, the signal is low. When pressed, the signal goes HIGH. This is required to wake the ESP32-S3 from deep sleep. This means you need to look for the signal to go high to track a button press. For example, in CircuitPython, you would use if button.value:.

D0 Button

The D0 button is doing double-duty on this Feather. It is both the BOOT button to enter the ROM bootloader, and available as an input in your code.

In CircuitPython, this button is available as board.D0, board.BOOT0, and board.BUTTON. (All three are the same pin!)

In Arduino, this button is available as 0.

This button is pulled HIGH by default, e.g. when not pressed, the signal is high. When pressed, the signal goes LOW. This means you need to look for the signal to go LOW to track a button press. For example, in CircuitPython, you would use if not button.value:.

To enter the ROM bootloader, hold down D0, and while holding, press the Reset button.

Reset Button(s) and RST Pin

• Reset button - There is a reset button located on both sides of the board. The reset button restarts the board and helps enter the bootloader. You can click it once to reset the board without unplugging the USB cable or battery. Alternatively, tap once, and then tap again while the NeoPixel status LED is purple to enter the UF2 bootloader (needed to load CircuitPython).
• The RST pin is can be used to reset the board. Tie to ground manually to reset the board.

Debug Pin

This is the Debug TX (DB) pin. This is the hardware UART debug pin. You can connect this to a USB console cable in order to read the debug output from the ESP32 IDF. This is useful if you are writing software and need to see the low level debug output.

This is not where default Serial.print() or CircuitPython print() outputs go - those will go through the USB port instead!