SDR104 SDIO3.0 card support on Apalis EVB V1.1A for Apalis iMX6 SoM

Technical Support
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1

Hi,

I have to bring up SDIO 3.0 card on Apalis EVB V1.1A SD1 4-bit mode SDIO port X19.
From Apalis iMX6 SoM datasheet, I can confirm that there is support for SDR104 mode.
Remove R29,R30,R31,R32,R39 pull ups near X19 connector to enable hardware support.

Also in imx6qdl-apalis.dtsi generated from oe-core Yocto Rocko build,

/* SD1 */
&usdhc2 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_usdhc2 &pinctrl_sd_cd>;
cd-gpios = <&gpio6 14 GPIO_ACTIVE_LOW>;
vqmmc-supply = <& reg_3p3v>;
bus-width = < 4 >;
voltage-ranges = < 3300 3300 >;
status = "disabled";
};

pinctrl_usdhc2: usdhc2grp {
	fsl,pins = <
		MX6QDL_PAD_SD2_CMD__SD2_CMD    0x17071
		MX6QDL_PAD_SD2_CLK__SD2_CLK    0x10071
		MX6QDL_PAD_SD2_DAT0__SD2_DATA0 0x17071
		MX6QDL_PAD_SD2_DAT1__SD2_DATA1 0x17071
		MX6QDL_PAD_SD2_DAT2__SD2_DATA2 0x17071
		MX6QDL_PAD_SD2_DAT3__SD2_DATA3 0x17071
	>;
};

So I think SDR104 should work straight away if I follow above changes right. Is my thinking correct?
Also can anyone please suggest us how to get to know information regarding pin name and values
Eg: MX6QDL_PAD_SD2_CMD__SD2_CMD 0x17071

Thanks,
Sridhar

2

Hi @sridhar.jonnavittula

So I think SDR104 should work straight away if I follow above changes right. Is my thinking correct?

Well, this depends on the SDIO card. If SDR104 is supported with 3.3V then SDR104 should work, but if your SDIO Card needs 1.8V then it will not work. Unfortunately Apalis iMX6 does not allow VoltageLevel Switching on SDIO Interfaces.

Also can anyone please suggest us how to get to know information regarding pin name and values Eg: MX6QDL_PAD_SD2_CMD__SD2_CMD 0x17071

You can find the Information regarding the pin name and values here and here respectively. Further you can check also the Datasheet of Apalis iMX6.

Best regards,
Jaski