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

#define MICROPY_HW_BOARD_NAME "Adafruit Itsy Bitsy 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)

// Saleae reads 12mhz which is the limit even though we set it to the safer 8mhz.
#define SPI_FLASH_BAUDRATE  (8000000)

#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
#define SPI_FLASH_MOSI_PIN_FUNCTION PINMUX_PB22D_SERCOM5_PAD2
#define SPI_FLASH_MISO_PIN_FUNCTION PINMUX_PB03D_SERCOM5_PAD1
#define SPI_FLASH_SCK_PIN_FUNCTION  PINMUX_PB23D_SERCOM5_PAD3
#define SPI_FLASH_SERCOM            SERCOM5
#define SPI_FLASH_SERCOM_INDEX      5
#define SPI_FLASH_MOSI_PAD          2
#define SPI_FLASH_MISO_PAD          1
#define SPI_FLASH_SCK_PAD           3
// <o> Transmit Data Pinout
// <0x0=>PAD[0,1]_DO_SCK
// <0x1=>PAD[2,3]_DO_SCK
// <0x2=>PAD[3,1]_DO_SCK
// <0x3=>PAD[0,3]_DO_SCK
#define SPI_FLASH_DOPO              1
#define SPI_FLASH_DIPO              1   // same as MISO pad

// These are pins not to reset.
#define MICROPY_PORT_A        (PORT_PA00 | PORT_PA01 | PORT_PA27 | PORT_PA24 | PORT_PA25)
#define MICROPY_PORT_B        (PORT_PB22 | PORT_PB23 | PORT_PB03 )
#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)

#include "external_flash/devices.h"

#define EXTERNAL_FLASH_DEVICE_COUNT 2
#define EXTERNAL_FLASH_DEVICES W25Q16FW, \
                               GD25Q16C

#include "external_flash/external_flash.h"

#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)