Radxa X4 Firmata

Boards.h

 // Raspberry Pi Pico
 // https://datasheets.raspberrypi.org/pico/Pico-R3-A4-Pinout.pdf
 #elif defined(TARGET_RP2040) || defined(TARGET_RASPBERRY_PI_PICO)
 #define TOTAL_ANALOG_PINS       4
 #define TOTAL_PINS              30
 #define VERSION_BLINK_PIN       LED_BUILTIN
 #define IS_PIN_DIGITAL(p)       (((p) >= 0 && (p) < 23) || (p) == LED_BUILTIN)
 #define IS_PIN_ANALOG(p)        ((p) >= 26 && (p) < 26 + TOTAL_ANALOG_PINS)
 #define IS_PIN_PWM(p)           digitalPinHasPWM(p)
 #define IS_PIN_SERVO(p)         (IS_PIN_DIGITAL(p) && (p) != LED_BUILTIN)
 // From the data sheet I2C-0 defaults to GP 4 (SDA) & 5 (SCL) (physical pins 6 & 7)
 // However, v2.3.1 of mbed_rp2040 defines WIRE_HOWMANY to 1 and uses the non-default GPs 6 & 7:
 //#define WIRE_HOWMANY	(1)
 //#define PIN_WIRE_SDA            (6u)
 //#define PIN_WIRE_SCL            (7u)
 #define IS_PIN_I2C(p)           ((p) == PIN_WIRE_SDA || (p) == PIN_WIRE_SCL)
 // SPI-0 defaults to GP 16 (RX / MISO), 17 (CSn), 18 (SCK) & 19 (TX / MOSI) (physical pins 21, 22, 24, 25)
 #define IS_PIN_SPI(p)           ((p) == PIN_SPI_SCK || (p) == PIN_SPI_MOSI || (p) == PIN_SPI_MISO || (p) == PIN_SPI_SS)
 // UART-0 defaults to GP 0 (TX) & 1 (RX)
 #define IS_PIN_SERIAL(p)        ((p) == 0 || (p) == 1 || (p) == 4 || (p) == 5 || (p) == 8 || (p) == 9 || (p) == 12 || (p) == 13 || (p) == 16 || (p) == 17)
 #define PIN_TO_DIGITAL(p)       (p)
 #define PIN_TO_ANALOG(p)        ((p) - 26)
 #define PIN_TO_PWM(p)           (p)
 #define PIN_TO_SERVO(p)         (p)