Reference
Last revision 2026/01/18
Library
- DFRobot_RTU Library: Download Link
- DFRobot_EnvironmentalSensor Library: Download Link
- DFRobot_AHT20 Library: Download Link
- DFRobot_GDL Library: Download Link
Communication Protocol Description
UART Communication
In Arduino development environment, Beetle RP2040 defines 3 groups of UART communication interfaces: UART0, UART1, UART2. USB-to-serial port is defined as UART0, which does not conflict with UART1 and UART2.
| NO. | UART Functions | Other Functions |
|---|---|---|
| GP4 | Serial2 / RX | SDA0 |
| GP5 | Serial2 / TX | SCL0 |
| GP28 | Serial1 / TX | A2 |
| GP29 | Serial1 / RX | A3 |
| USB | Serial |
The following is the definition of the UART interface in "pins_arduino.h" file:
#define PIN_SERIAL1_TX (28u)
#define PIN_SERIAL1_RX (29u)
#define PIN_SERIAL2_TX (4u)
#define PIN_SERIAL2_RX (5u)
I2C Communication
The Beetle RP2040 provides two groups of I2C communication interfaces: I2C0 and I2C1. The pinouts are as follows:
| NO. | I2C Function | Other Functions |
|---|---|---|
| GP2 | I2C1/SDA | SPI0/SCK |
| GP3 | I2C1/SCL | SPI0/MOSI |
| GP4 | I2C0/SDA0 | RX2 |
| GP5 | I2C0/SCL0 | TX2 |
The default I2C interface is I2C0 in Arduino because I2C1 overlaps with some pins of SPI while I2C0 is only multiplexed with the seldom-used UART1.
SPI Communication
Beetle RP2040 supports full-duplex SPI communication. The pinouts are as follows:
| No. | SPI Function | Other Functions |
|---|---|---|
| GP0 | SPI0/MISO | |
| GP1 | SPI0/CSn | |
| GP2 | SPI0/SCK | SDA1 |
| GP3 | SPI0/MOSI | SCL1 |
Other Supplementary Information
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