Introduction

Beetle CM-32U4, an upgraded version of DFRobot Beetle Board, adds a charge management function while retaining the original advantages like rich functions and small size. Users can use the battery pack to power the project or charge the battery via USB, which can greatly increase the service life when using this little board in "one-off" compact projects. There are 3 power supply methods: USB power supply; Battery pack power supply on the BAT pin; 5V external power supply on the VIN pin. Features like compact size, being rechargeable and diverse power supplies make this board more widely applicable to DIY projects, workshops, gift projects, E-Textiles wearable, and educational.

Beetle CM-32U4 is fully compatible with Arduino, please select “Arduino Leonardo” when using.

Feature

Compact size and easy to integrate
3 power supply methods:
- USB power supply
- Battery pack power supply (Only 3.7V lithium battery can be connected to BAT port.)
- 5V VIN external power supply (The input voltage range of VIN is 4.5-6V. )
Charging function: can charge 3.7V lithium battery
3 indicators onboard:
- Red: power indicator (PWR)
- Blue: normal LED (L)
- Green: charging indicator

Specification

尺寸图

Mainboard: Beetle CM-32U4
Microcontroller： ATmega32U4
Flash Memory：2 KB of which 4KB used by bootloader
SRAM：2.5KB
Clock Rate：16 MHz
Charging chip: TP4056X
Operating Voltage: 5V (DC)
Operating Temperature: -40～125℃
charging current: 200mA ~ 600mA
I2C: 1 WIRE library
SPI: 1 SPI library
UART: 1
Power Port: 3
Dimension: 22 × 20.5mm/0.87 x 0.81”

Board Overview

引脚图

Requirements

Hardware
- Beetle CM-32U4
- 1000mAh lithium Battery
- USB Cable
Software
- Arduino IDE

Board Selection

板卡选择

For any questions, advice or cool ideas to share, please visit the DFRobot Forum(https://www.dfrobot.com/forum/).

Indicator Status description

Status	Power Indicator(red)	LED Light(blue)	Charging Indicator(green)
OFF	Mainboard Power off	Can be set	Fully charged
ON	Mainboard Power on	Can be set	Charging
Flash	Burning Codes/Resetting	Resetting/can be set	No battery

The blue LED light can also be used as a normal LED, and you can download Blink.ino to control it. The pin number is 13.

Introduction of Charging Process

Prepare a 1000mAh lithium battery. Connect the positive of the battery to BAT on the Beetle CM-32U4 and the negative to GND, and then connect to the USB charging cable.

充电现象

At this time, the BAT port will charge the battery with an input current of 200mA~600mA and the green charging light will present the current status of the battery:

Status	Charging Indicator(green)
OFF	Fully charged
ON	Charging
Flash	No battery

Introduction of Resetting

复位现象

NOTE: Only the red power indicator and blue indicator will be affected during the RST process.

Beetle CM-32U4 Compatible with Arduino Leonardo - ATmega32U4 Wiki - DFRobot