Hello,
I am currently using an STM32U5G9 and would like to connect a microSD card via SDMMC1 to expand data storage. My Zephyr devicetree contains the following node:
&sdmmc1 {
status = "okay";
pinctrl-0 = <&sdmmc1_d0_pc8 &sdmmc1_d1_pc9 &sdmmc1_d2_pc10 &sdmmc1_d3_pc11
&sdmmc1_ck_pc12 &sdmmc1_cmd_pd2>;
pinctrl-names = "default";
disk-name = "SD";
bus-width = <1>;
clk-div = <8>;
};
As shown above, bus-width = <1> indicates 1-bit (1-line) mode. I would like to use 4-bit mode, but after changing this value to <4>, the microSD card can no longer be accessed.
How should this issue be resolved, and what additional configuration or considerations are required to enable 4-bit SDMMC operation correctly on STM32U5 with Zephyr?
