The Feather STM32F405 Express uses SDIO to connect its built in micro SD card slot. Didn't notice it had an SD card slot? We hid it on the underside.
To mount the SD card, use the following code. Remember to put it in the file mount_sd.py on CIRCUITPY so you can easily call it from code.py or the REPL with import mount_sd
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import board import sdioio import storage sdcard = sdioio.SDCard( clock=board.SDIO_CLOCK, command=board.SDIO_COMMAND, data=board.SDIO_DATA, frequency=25000000) vfs = storage.VfsFat(sdcard) storage.mount(vfs, "/sd")

