ESP32 Thing Plus (USB-C) Hookup Guide

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Hardware Overview

Board Dimensions

The board dimensions are illustrated in the drawing below. The listed measurements are in inches and the two mounting holes are compatible with 4-40 standoff screws.

USB-C Connector

The USB connector is provided to power and program the board. For most users, it will be the primary programing interface for the ESP32.

CH340 Serial-to-UART

The CH340 allows the ESP32-WROOM to communicate with a computer/host device through the board's USB-C connection. This allows the board to show up as a device on the serial (or COM) port of the computer. Users will need to install the latest drivers for the computer to recognize the board (see Software Overview section).

Power

The ESP32-WROOM Thing Plus only requires 3.3V to power the board. However, the simplest method to power the board is through the USB-C connector. Alternatively, the 3V3, VBAT, and VUSB pins can also be used to supply power to the board.

• VUSB:
  • The maximum voltage for the LDOs and charge controller is 6V.
  • The minimum voltage for the charge controller is 3.75V.
• VBAT:
  • Should not be connected to anything other than a single-cell LiPo battery.
• 3V3:
  • Requires a regulated 3.3V.
  • Only powers the board and not the Qwiic connector.

Below, is a general summary of the power circuitry on the board:

• 3V3 - Provides a regulated 3.3V from the USB (5V) power and/or battery connections.
  • Used to power the ESP32-WROOM module, µSD card slot, WS2812 RGB LED, CH340C Serial-to-UART bridge, and power LED.
    • The Qwiic connector is powered by its own voltage regulator, from the same power source(s).
  • The 3.3V XC6222 LDO regulator can source up to 700mA.
    • Output is controlled by the EN pin on the board.
• VUSB - The voltage from the USB-C connector, usually 5V.
  • Power source for the entire board.
    • Powers the 3.3V voltage regulators and the battery charging circuit for VBAT.
  • Overides power from the battery through a P-channel MOSFET, when both are connected.
  • Utilizes a BAT20J protection diode for the USB-C connection.
• VBAT - The voltage from the JST battery connector; meant for single cell LiPo batteries.
  • Provides power to the 3.3V voltage regulators and MAX17048 battery fuel gauge.
  • The MCP73831 linear charge management controller is powered from the USB (5V) power supply.
    • The charge controller is configured for 500mA (max) rate of charge to a connected battery.
• GND - The common ground or the 0V reference for the voltage supplies.
• Qwiic Connector - Provides a regulated 3.3V voltage from the USB (5V) power and/or battery connections.
  • Operates independently from the 3V3 pin, with its own voltage regulator.
  • The 3.3V XC6222 LDO regulator can source up to 700mA.
    • Output is controlled by GPIO 0 of the ESP32-WROOM.

For more details, users can reference the schematic and the datasheets of the individual components in the power circuitry.

Power Status LED

The red, PWR LED will light up once 3.3V is supplied to the board; however, for most users, it will light up when 5V is supplied through the USB connection or when a LiPo battery is connected to the JST connector.

Charging Circuit

The charging circuit utilizes the MCP73831 linear charge management controller and is powered directly from the USB-C connector or VUSB. The controller is configured for a 500mA charge rate and active charging is indicated by the yellow, CHG LED. If the charge controller is shutdown or charging is complete, the CHG LED will turn off. For more information, please refer to the MCP73831 datasheet and the Indicator LEDs section below.

Power Control

The power source for the XC6222 LDO voltage regulators is controlled by a P-channel MOSFET. In addition, the 3.3V regulated output from the XC6222 LDOs are enabled by the control pin (CE).

The P-channel MOSFET operates based on the voltages at the MOSFET's gate and source pins. Depending on the power supplies connected to the board, the MOSFET will switch between the battery and USB-C connection as power sources for the XC6222 voltage regulators.

Power Source	MOSFET				Power Control Description
	Gate	Source	VGS (VGate - VSource)	MOSFET Operation
USB Only	VUSB = 5V	VUSB - Vf	VUSB - (VUSB - Vf) VGS = Vf	MOSFET Off RGS = ∞ Switch Open	Power to the XC6222 is supplied by the USC-C connection. Power from the USB-C connection is passed through the Schottky diode. Due to the voltage drop from the Schottky diode, the gate threshold voltage for the MOSFET is positive and equivalent to the diode's forward voltage (Vf).Therefore, the MOSFET behaves as an open switch.
Battery Only	VUSB = 0V	Dep. Mode: VSource = 0 Charged Cap.: VBatt = 3 - 4.2V	Dep. Mode: VGS = 0 Charged Cap.: VUSB - VBatt = -VBatt -3V > VGS > -4.2V	MOSFET On RGS = Low Switch Closed	Power to the XC6222 is supplied from the battery connection. As a depletion type P-channel MOSFET, the mosfet acts as a normally closed switch when the gate threshold voltage is zero. Therefore, power from the battery is able to charge the capacitor and create a negative gate threshold voltage. The MOSFET remains behaving as a closed switch and power to the XC6222 is provided from the battery.
USB & Battery	VUSB = 5V	VUSB - Vf	VGS = Vf	MOSFET Off RGS = ∞ Switch Open	Power to the XC6222 is supplied by the USC-C connection. Power from the USB-C connection is passed through the Schottky diode. Due to the voltage drop from the Schottky diode, the gate threshold voltage for the MOSFET is positive and equivalent to the diode's forward voltage (Vf).Therefore, the MOSFET behaves as an open switch.

The control pin (CE) of the XC6222 LDOs also provides an additional amount of control for the board's power. By default, the regulated 3.3V output is enabled. To disable and shutdown the output voltage from the XC6222, the control pin needs to be pulled low (i.e. shorted to ground (GND)). For more information, please refer to the XC6222 datasheet.

• The 3.3V power for the board (3V3) is controlled by the EN pin, which is broken out on the board.
• The 3.3V power for the Qwiic connector is controlled by GPIO 0 of the ESP32-WROOM.

Current Consumption

According to the specifications, the ESP32-WROOM draws about 240 mA during RF transmissions. With the WiFi example in this tutorial, have measured it to average around 140 mA and peak at 300 mA while actively transceiving. The table below, summarizes the approximate current draw of the ESP32-WROOM Thing Plus (USB-C) for various operational conditions. The measurements in the table below, were made with the Nordic Power Profiler Kit II.

Operation	Avg. Current Draw
	LiPo: 3.5V (Low < 5%)	LiPo: 3.7V (~15%)	LiPo: 4.2V (~100%)	USB-C: 5V (No Battery)
Idle (Blank Code)	63 mA 86 mA (peak)	63.5 mA 89 mA (peak)	64 mA 88.6 mA (peak)	67 mA 89.9 mA (peak)
Idle: USB + Battery Power (Current from Battery)	--	--	90.5 µA 721 µA (peak)	N/A
Idle: Battery Charging (Current from USB-C)	395 mA 420 mA (peak)	590 mA 600 mA (peak)	> 110 mA (before shutdown)	N/A
RGB (White @ 100%)	78.4 mA 105.9 mA (peak)	79 mA 106.8 mA (peak)	79.9 mA 105.3 mA (peak)	82.5 mA 108.2 mA (peak)
WiFi Example (Transceiving)	135 mA 295 mA (peak)	137 mA 310 mA (peak)	137 mA 307 mA (peak)	140 mA 300 mA (peak)
Deep Sleep Example (MCU Inactive)	2.5 mA 2.95 mA (peak)	2.5 mA 3 mA (peak)	2.55 mA 3 mA (peak)	2.85 mA 3.3 mA (peak)
Deep Sleep Example (MCU Inactive + Jumpers Cut)	842 µA 1.24 mA (peak)	848 µA 1.23 mA (peak)	866 µA 1.24 mA (peak)	1.19 mA 1.58 mA (peak)

It is possible for users to reach sub-mA power consumption levels with the deep sleep power modes. Using the TimerWakeUp Deep Sleep example code, the LED jumpers cut, and powering the board through the LiPo battery connection we measured a power consumption of 845 µA (990 µA peak) @ 3.7V while the MCU was inactive.

ESP32-WROOM

This variant of the ESP32 Thing Plus is designed around the ESP32-WROOM module with 16MB of flash memory. Espressif's ESP32-WROOM module is a versitile, WiFi+BT+BLE MCU module that targets a wide variety of applications. At the core of this module is the ESP32-D0WDQ6 system on a chip (SoC) which is designed to be both scalable and adaptive. Its laundry list of features include:

Debugging

For users interested in debugging their code, the JTAG pins are broken out on the board. However, the debugging feature is only available through the ESP-IDF.

• TMS: GPIO 14
• TDI: GPIO 12
• TCK: GPIO 13
• TDO: GPIO 15

Firmware Download Mode

Users can manually force the board into the serial bootloader with the BOOT button. Please, refer to the Boot Button section below for more information.

Peripherals and I/O

The ESP32-WROOM module has 26 multifunctional GPIO, of which, 21 I/O pins broken out into a feather form factor layout on this board. All of the ESP32-WROOM Thing Plus (USB-C) pins have a .1" pitch spacing for headers. With the pin multiplexing capabilities of the ESP32 SoC, various pins can have several functionalities. For more technical specifications on the I/O pins, please refer to the ESP32 SoC datasheet.

• 13x 12-bit analog to digital converter (ADC) channels
• 3x UARTs (only two are configured by default in the Arduino IDE, one UART is used for bootloading/debug)
• 3x SPI (only one is configured by default in the Arduino IDE)
• 2x I²C (only one is configured by default in the Arduino IDE)
• 2x I²S Audio
• 2x digital-to-analog converter (DAC) channels
• 16x 20-bit PWM outputs
• 8x Capacitive Touch Inputs

For digital pins, users will need to declare the pinMode() (link) in the setup of their sketch (programs written in the Arduino IDE) for the pins used.

Input

When configured properly, an input pin will be looking for a HIGH or LOW state. Input pins are High Impedance and takes very little current to move the input pin from one state to another.

Output

When configured as an output the pin will be at a HIGH or LOW voltage. Output pins are Low Impedance: This means that they can provide a relatively substantial amount of current to other circuits.

Additional Functions

There are several pins that have special functionality in addition to general digital I/O. These pins and their additional functions are listed in the tabs below. For more technical specifications on the I/O pins, you can refer to the schematic, ESP32-WROOM module datasheet, ESP32 SoC datasheet, and documentation for the ESP32 Arduino core.

Buttons

There are two buttons on ESP32-WROOM Thing Plus; a RST and BOOT button.

Reset Button

The RST (reset) button allows users to reset the program running on the ESP32-WROOM module without unplugging the board.

Boot Button

The BOOT button can be used to force the board into the serial bootloader. Holding down the BOOT button, while connecting the board to a computer through its USB-C connector or resetting the board will cause it to enter the Firmware Download mode. The board will remain in this mode until it power cycles (happens automatically after uploading new firmware) or the RST button is pressed.

1. Hold the BOOT button down.
2. Reset the MCU.
   • While unpowered, connect the board to a computer with through the USB-C connection.
   • While powered, press the RST button.
3. Release the BOOT button.
4. After programming is completed, reboot the MCU.
   • Press the RST button.
   • Power cycle the board.

Indicator LEDs

There are four indicator LEDs on the ESP32-WROOM Thing Plus:

• PWR: Power (Red)
• CHG: Battery Charging (Yellow)
• 13: GPIO 13 (Blue)
• WS2812: GPIO 02 (RGB)

Power LED

The red, power (PWR) LED will light up once 3.3V is supplied to the board. For most users, it will light up when 5V is supplied through the USB connection and/or when a LiPo battery is attached to the JST connector.

Battery Charging LED

The yellow, battery charging (CHG) LED indicates the status of the MCP73831 charge management controller. The LED will shut off when no battery is present, when the charge management controller is in standby (after the battery charging has been completed), or when the charge management controller is shutdown. The LED will illuminate when the charge management controller is in the process of charging the battery. For more information, please refer to the MCP73831 datasheet.

STAT LED

The blue, status (STAT) LED is typically used as a test or status LED to make sure that a board is working or for basic debugging. This indicator is connected to GPIO 13.

WS2812 RGB LED

The WS2812 RGB LED is controlled with a 24-bit (GRB) data signal. This indicator is connected to GPIO 02 and the digital output pin from the LED is available through a test point. For more information, please refer to the WS2812C datasheet.

µSD Slot

The ESP32-WROOM Thing Plus (USB-C) includes an µSD card slot. This is great for data logging applications or storing files. The µSD card slot is connected to the following dedicated GPIO:

• GPIO 5: DATA 3/CS
• N/A: DATA 2
• N/A: DATA 1
• GPIO 19: DATA 0/POCI (or Peripheral's SDO)
• GPIO 18: CLK/SCK
• GPIO 23: CMD/PICO (or Peripheral's SDI)

Jumpers

There are two jumpers on the back of the board that can be used to easily modify the hardware connections on the board.

• SHLD - This jumper can be used to disconnect the USB shield from GND.
• PWR - This jumper can be used to remove power to the PWR LED.
• CHG LED - This jumper can be used to remove power to the CHG LED.
  • Avoid cutting the box's silkscreen; there are traces under it:
    
    Traces around the CHG LED jumper. (Click to enlarge)

Primary I²C Bus

The Qwiic connector and battery fuel gauge are attached to the primary I²C bus. The primary I²C bus for this board utilizes the pin connections, detailed in the table below:

Connection	VDD	GND	SCL	SDA
Battery Fuel Gauge (MAX17048)	VBAT	GND	GPIO 22	GPIO 21
Qwiic Connector	GPIO 0 (Enables 3.3V)	GND	GPIO 22	GPIO 21

Battery Fuel Gauge

The MAX17048 fuel gauge measures the approximate charge or discharge rate, state of charge (SOC) (based on ModelGauge algorithm), and voltage of a connected battery. Additionally, the chip is powered directly from VBAT, when a LiPo battery is connected. For more information, please refer to the MAX17048 datasheet.

Qwiic Connector

A Qwiic connector is provided for users to seamlessly integrate with SparkFun's Qwiic Ecosystem.

Power Control

In order to enable power for the Qwiic connector, users must toggle GPIO 0 high. This enables the power output from the XC6222 LDO regulator to the Qwiic connector, which can sources up to 700mA at 3.3V . In order to conserve battery power or in low power applications, users will can toggle GPIO 0 low, to disable the power to the Qwiic connector.

What is Qwiic?

The Qwiic system is intended a quick, hassle-free cabling/connector system for I²C devices. Qwiic is actually a play on words between "quick" and I²C or "iic".

Features of the Qwiic System

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