Example Code for Arduino-SPI Communication

Hardware Preparation

• DFRobot Beetle RP2040, 1, Purchase Link
• USB Type-C Cable, 1
• Fermion: 1.8" 128x160 IPS TFT LCD Display (DFR0928), 1, Purchase Link

Software Preparation

• Arduino IDE: Download Link
• Raspberry Pi Pico/RP2040 SDK: Installed via Arduino Boards Manager (see Getting Started)
• DFRobot_GDL Library: Download Link

Wiring Diagram

• BeetleRP2040: GP0 (connect to) Display: MISO
• BeetleRP2040: GP2 (connect to) Display: SCLK
• BeetleRP2040: GP3 (connect to) Display: MOSI
• BeetleRP2040: GP4 (connect to) Display: DC
• BeetleRP2040: GP5 (connect to) Display: CS
• BeetleRP2040: GP28 (connect to) Display: RES
• BeetleRP2040: GND (connect to) Display: GND
• BeetleRP2040: 3V3 (connect to) Display: VCC

Other Preparation Work

1. Open Arduino IDE.
2. Select "DFRobot Beetle RP2040" as the development board.
3. Connect the Beetle RP2040 to your computer.
4. Wire the TFT display to SPI0 (GP0/MISO, GP1/CSn, GP2/SCK, GP3/MOSI) as per the diagram.
5. Install the DFRobot_GDL library via Arduino Library Manager.

Sample Code

Function: make the LCD display connected to the SPI of the RP2040 display the text "DFRobot".

#include "DFRobot_GDL.h"

#define TFT_DC  4
#define TFT_CS  5
#define TFT_RST 28

DFRobot_ST7735_128x160_HW_SPI screen(/*dc=*/TFT_DC,/*cs=*/TFT_CS,/*rst=*/TFT_RST);

void setup() {
  screen.begin();
  screen.setTextSize(1);
  screen.fillScreen(COLOR_RGB565_BLACK);
  screen.setFont(&FreeMono12pt7b);
  screen.setCursor(/*x=*/32,/*y=*/64);
  screen.setTextColor(COLOR_RGB565_LGRAY);
  screen.setTextWrap(true);
  screen.print("DFRobot");
}

void loop() {

}

Result

The display shows the text "DFRobot" in the center of the screen.

Additional Information

• SPI0 uses pins GP0 (MISO), GP1 (CSn), GP2 (SCK), and GP3 (MOSI) for communication.
• The TFT display uses hardware SPI for fast data transfer.