FireBeetle 2 ESP32-E IoT Microcontroller

1. Getting Started

2. Example Code for Arduino-Blink a LED

3. Example Code for Arduino-GPIO

4. Example Code for Arduino-RGB LED

5. Example Code for Arduino-Serial Port

6. Example Code for Arduino-I2C Communication

7. Example Code for Arduino-SPI Communication

8. Example Code for Arduino-Capacitive Touch

9. Example Code for Arduino-Interrupt

10. Example Code for Arduino-GDI Display interface

11. Example Code for Arduino-SD Card

12. Example Code for Arduino-Deep-sleep Mode

13. Example Code for Arduino-WiFi

14. Example Code for Arduino-Bluetooth

15. Example Code for Arduino-IFTTT

Reference

Power Parameters

Parameter	Details
Input Voltage	USB-C Port: 5V DC PH2.0 Connector: 3.7~4.2V Li-ion VCC Pin: 5V DC

MCU Parameters

Parameter	Details
Processor	Xtensa Dual-Core 32-bit LX6 Microprocessor
Clock Speed	240 MHz
SRAM	520 KB
ROM	448 KB
Flash Memory	4 MB

Wireless Parameters

Parameter	Details
Wi-Fi Standard	FCC/CE/TELEC/KCC
Wi-Fi Protocol	802.11 b/g/n/d/e/i/k/r (802.11n, up to 150 Mbps), A-MPDU and A-MSDU aggregation, supports 0.4us protection interval
Wi-Fi Frequency Range	2.4~2.5 GHz
Bluetooth Protocol	Compliant with Bluetooth V4.2 BR/EDR and BLE standards
Bluetooth Audio	CVSD and SBC audio
Bluetooth Frequency Range	2.4~2.5GHz

Peripheral Parameters

Parameter	Details
Digital Pins	× 18 (IO0, IO1, IO2, IO3, IO4, IO12, IO13, IO14, IO15, IO16, IO17, IO18, IO19, IO21, IO22, IO23, IO25, IO26)
Analog Pins	× 11 (IO0, IO2, IO4, IO12, IO13, IO14, IO15, IO25, IO26, I34, I35)
UART Interfaces	× 2
SPI Interface	× 1
I2C Interface	× 1
I2S Interface	× 1
DAC Interfaces	× 2
Touch Interfaces	× 7
LED PWM Channels	× 16
RGB LED	WS2812
Display Interface	GDI

Physical Parameters

Parameter	Details
Module Size	25.4mm × 60mm
Mounting hole size	hole diameter 2.0mm
Weight	23.4g

Board Overview

DFR0564-Board Overview

No.	Function	Description
①	USB Interface	Program download and power supply, 4.75V-5.5V compatible
②	Charging Indicator	Red LED for indicating charging status: 1. Off when fully charged or not charged; 2. On when charging; 3. Quick flash when powered by USB, and no battery connected.
③	User Button	Controlled by pin IO27/D4
④	Li-ion Battery Port	Support 3.7V-4.2V
⑤	Onboard RGB Light	WS2812 RGB LED, controlled by pin IO5/D8
⑥	Onboard LED	LED controlled by pin IO2/D9
⑦	Reset Button	Press to reset program
⑧	Low-power Solder Jumper Pad	Designed for low power mode and default to be connected. Slightly cut off the thin wire with a knife to disconnect it. When disconnected, static power consumption can be reduced by 500 μA. The power consumption can be reduced to 2mA after controlling the maincontroller to enter the sleep mode through the program. Note: when the pad is disconnected, you can only drive RGB LED light via the USB Power supply.
⑨	GDI	DFRobot dedicated Display interface. Refer to the GDI part of this page.
⑩	ESP32-E Chip	ESP32-WROOM-32E

Pinout

DFR0654-Pinout

Categroy	Description
Control	FireBeetle enable/reset pins
Touch	Pin with capacitive touch function
Analog	Analog pin
Port PIN	Default physical pin number of the chip, which can be used to directly control the corresponding pin
Arduino IDE	In Arduino IDE, the pin numbers have been remapped by FireBeetle, and you can directly use this symbol to control the corresponding pin
RTC PIN	FireBeetle 2 ESP32-E supports low power function, and in Deep-sleep mode, only RTC pin keeps working and can be used as a wave-up source. When RTC pin is used as an output pin, it keeps outputting level value when the chip is in Deep-sleep mode, while as an input pin, it can wake up the chip from Deep-sleep.
GND	Common ground for all power supplies and logics
Power	When powered by 5V-USB, VCC outputs about 4.7V and 3V3 outputs 3.3V; When powered by 4V li-ion battery, VCC outputs about 4V and 3V3 outputs 3.3V(Actual measurement)

FireBeetle 2 ESP32-E has up to 24 physical GPIOs, which are mainly for connecting peripherals like sensors, actuators, etc. Meanwhile, these IO pins can be multiplexed for other functions such as UART, SPI, I2C and so on. The table below provides users with a detailed description of FireBeetle 2 ESP32-E GPIO.

Pin Number	Name	Function	ADC	Communication	Remark
GPIO 0	0/D5	Used as input or output	ADC2_CH1		Occupied when using USB transmission
GPIO 1	1/TXD	Used as input or output		UART0_TX	Occupied when using USB power supply and serial printing
GPIO 2	2/D9	Used as input or output	ADC2_CH2		For controlling onboard LED by outputting digital signal
GPIO 3	3/RXD	Used as input or output		UART0_RX	Occupied when using USB power supply and serial printing
GPIO 4	4/D12	Used as input or output	ADC2_CH0
GPIO 12	12/D13	Used as input or output	ADC2_CH5
GPIO 13	13/D7	Used as input or output	ADC2_CH4
GPIO 14	14/D6	Used as input or output	ADC2_CH6
GPIO 15	15/A4	Used as input or output	ADC2_CH3
GPIO 18	18/SCK	Used as input or output		SPI_SCK
GPIO 19	19/MISO	Used as input or output		SPI_MISO
GPIO 21	21/SDA	Used as input or output		I2C_SDA
GPIO 22	22/SCL	Used as input or output		I2C_SCL
GPIO 23	23/MOSI	Used as input or output		SPI_MOSI
GPIO 25	25/D2	Used as input or output	ADC2_CH8		DAC_1（Range: 0-255; Output Voltage: 0-3.3V）
GPIO 26	26/D3	Used as input or output	ADC2_CH9		DAC_2（Range: 0-255; Output Voltage: 0-3.3V）
GPIO 34	34/A2	Used as input only	ADC1_CH6
GPIO 35	35/A3	Used as input only	ADC1_CH7
GPIO 36	36/A0	Used as input only
GPIO 39	39/A1	Used as input only

Note:

It is recommended not to multiplex the pin IO0/D5, IO1/TXD and IO3/RX since they will be occupied when using USB-related function. The USB-related circuit design is shown below:

DFR0654-USB Schematic

IO34-39 are for input only.
FireBeetle 2 ESP32-E has two 8-bit DAC channel that converts 2-way digital signal to 2 analog voltage outputs. Two channels can work independently. DAC circuit is composed of built-in resistors in series and a buffer. The two DACs can be used as reference voltage.