STM32MP257F-DK SDIO 3.0 Issue (UHS Mode)

[mayank_7117]

I'm working with the STM32MP257F-DK board and using the NXP IW612 wireless module, which is connected through the Murata uSD-M.2 adapter via the board's microSD card slot.
When I connect the adapter, the mmc interface detects it in high-speed mode, with a clock frequency of 50 MHz and a signal voltage of 3.3 V.
To cross-check, I connected a standard SD card to the same slot, and it was correctly detected in UHS mode with a 100 MHz clock and 1.8 V signal voltage.
I want the Murata adapter (with IW612) to operate in UHS mode, using:
 A higher clock frequency (e.g., 100 MHz or above)
1.8 V signaling (switch from default 3.3 V)

What steps are required to achieve this?
 Do I need to modify the Device Tree(DTB)?
 Are any voltage regulators or GPIO controls required to enable the 1.8 V switch?
 What are the minimum hardware/software dependencies to ensure UHS mode is enabled for the SDIO interface used by the IW612?

[PatrickF]

Hi,

SD-Card UHS-I (max frequency and voltage) is negotiated during card initialization as per standard (i.e. to find a common mode possible on both host and card).

If the card does not behave as SD-Card (seems the case), the Linux framework/driver might not being able to setup things correctly. Please first check that with card manufacturer.

Probaby need some updates on Device Tree like as we have on SDMMC3 for embedded WLAN/BT module (but for SDMMC1, default supply for SD-Card is 3.3V, so you should also change LDO8 voltage if you want static 1.8V behavior). I'm not expert on this.

Another (better) option for Wifi 6 is to use STM32MP257F-EV1 and connect it using PCIe .

Regards.