circuitpython/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.h

#define MICROPY_HW_BOARD_NAME "Adafruit ItsyBitsy M0 Express"
#define MICROPY_HW_MCU_NAME "samd21g18"

#define CIRCUITPY_BITBANG_APA102
#define MICROPY_HW_APA102_MOSI   (&pin_PA01)
#define MICROPY_HW_APA102_SCK    (&pin_PA00)

#define SPI_FLASH_MOSI_PIN          &pin_PB22
#define SPI_FLASH_MISO_PIN          &pin_PB03
#define SPI_FLASH_SCK_PIN           &pin_PB23
#define SPI_FLASH_CS_PIN            &pin_PA27

// These are pins not to reset.
#define MICROPY_PORT_A        (PORT_PA00 | PORT_PA01)
#define MICROPY_PORT_B        (0)
#define MICROPY_PORT_C        (0)

// If you change this, then make sure to update the linker scripts as well to
// make sure you don't overwrite code.
#define CIRCUITPY_INTERNAL_NVM_SIZE 256

#define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - CIRCUITPY_INTERNAL_NVM_SIZE)

#define DEFAULT_I2C_BUS_SCL (&pin_PA23)
#define DEFAULT_I2C_BUS_SDA (&pin_PA22)

#define DEFAULT_SPI_BUS_SCK (&pin_PB11)
#define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
#define DEFAULT_SPI_BUS_MISO (&pin_PA12)

#define DEFAULT_UART_BUS_RX (&pin_PA11)
#define DEFAULT_UART_BUS_TX (&pin_PA10)

// USB is always used internally so skip the pin objects for it.
#define IGNORE_PIN_PA24     1
#define IGNORE_PIN_PA25     1