I have now turned on the debug option, started the development board and reported the following error:
k210_sdinitialize: Initializing bit bang SPI for the MMC/SD slot spi_setmode: mode=0 k210_sdinitialize: Successfully initialized bit bang SPI for the MMC/SD slot k210_sdinitialize: Binding bit bang SPI device to MMC/SD slot 0 spi_lock: lock=1 spi_setmode: mode=0 spi_setmode: mode=0 exchange=0x8000f2a4 spi_setbits: nbits=8 spi_setfrequency: frequency=400000 holdtime=55 actual=401445 spi_setfrequency: frequency=400000 holdtime=55 actual=401445 mmcsd_mediainitialize: Send CMD0 spi_select: devid=65536 selected=1 mmcsd_sendcmd: ERROR: Failed: i=9 response=ff spi_select: devid=65536 selected=0 mmcsd_mediainitialize: Send CMD0 spi_select: devid=65536 selected=1 mmcsd_sendcmd: ERROR: Failed: i=9 response=ff spi_select: devid=65536 selected=0 mmcsd_mediainitialize: ERROR: Send CMD0 failed: R1=ffffffff spi_select: devid=65536 selected=0 spi_lock: lock=0 spi_lock: lock=0 k210_sdinitialize: Successfully bound bit bang SPI device to MMC/SD slot 0 I created a new k210_mmcsd.c file with reference to the sam_mmcsd.c file, defined the spi_select, spi_status, and spi_cmddata functions in the file, and defined the k210_mmcsd_spiinitialize function to configure and initialize GPIO, and finally defined the k210_sdinitialize function, and called k210_sdinitialize in the k210_bringup function.
