RP2040 Arduino boards pin incompatiblity and solution

[Bodmer]

When using the RP2040 processor, the TFT_eSPI library expects pin number in the setup files to be the GPIO number, NOT the Arduino Dxx pin number. Unfortunately this causes problems with boards such as the Arduino RP2040 Nano Connect when using the Arduino RP2040 Mbed board package.

If you are using this library with an Arduino RP2040 board that is NOT a Rapsberry Pi Pico then the pin numbers must be in the following format in the setup file: px where x in the GPIO number. Example for GPIO 6.

#define TFT_SCLK  p6

Earle Philhower's R2040 support package is, in my opinion, supperior to the Arduino package but also has a problem with Arduino branded boards. When using that board package then use the Dx format where x is the Arduino pin number:

#define TFT_SCLK  D13

Here is an example Arduino board pinout. In this case Arduino D13 is GPIO 6 so the above are valid for that pin:

[Bodmer]

This type of pin definition is the setup file will allow the Arduino Nano Connect to work with both the Arduino Mbed board package and Earle Philhower's package.

// The TFT_eSPI library always uses GPIO numbers, this means the following pin designators
// must be used dependant on the RP2040 board package loaded
// For the Arduino Mbed package the GPIO numbers must be used prefixed with p:
#ifdef ARDUINO_ARCH_MBED
  #define TFT_MISO   p4  // Arduino pin D12
  #define TFT_MOSI   p7  // Arduino pin D11
  #define TFT_SCLK   p6  // Arduino pin D13
  #define TFT_CS     p5  // Arduino pin D10
  #define TFT_DC    p20  // Arduino pin D8
  #define TFT_RST   p21  // Arduino pin D9
  #define TOUCH_CS  p19  // Arduino pin D7
#else // For Earle Philhower's package the Arduino Dx pin designations must be used:
  #define TFT_MISO  D12
  #define TFT_MOSI  D11
  #define TFT_SCLK  D13
  #define TFT_CS    D10  // Chip select control pin
  #define TFT_DC    D8   // Data Command control pin
  #define TFT_RST   D9   // Reset pin (could connect to Arduino RESET pin)
  #define TOUCH_CS  D7
#endif