The MMC/SD connector on the STM-P103 seems to be wired for use in native MMC mode, with one bi-directional data line and one clock. The STM32f103 chip, on the other hand, has an SPI interface that uses data in and data out: if it can do MMC mode there’s very little in the STM32f10x reference manual on how to program it in that mode.
Of course MMC cards can work in SPI mode too but then you’d have to connect Pin 7 (DO) to SPI2_MISO on the controller chip and that connection is not designed into the board.
It could be programmed by setting the ports up as GPIO and bit-banging but that seems a waste of the potential capability of the STM32.
So how is the MMC/SD card expected to be programmed on the STM32-P103?