tuning failed for SDR50

litzchee — Thu, 17 Jul 2025 08:10:25 GMT

I am using an iMX8qxp on my custom board and I am experiencing tuning failed error when inserting a SDR50 SD card. This issue does not happen when I insert a SDR104 card.

Here is the device tree configuration

usdhc2: mmc@5b020000 { interrupts = <GIC_SPI 233 IRQ_TYPE_LEVEL_HIGH>; reg = <0x5b020000 0x10000>; clocks = <&sdhc1_lpcg 1>, <&sdhc1_lpcg 0>, <&sdhc1_lpcg 2>; clock-names = "ipg", "per", "ahb"; assigned-clocks = <&clk IMX_SC_R_SDHC_1 IMX_SC_PM_CLK_PER>; assigned-clock-rates = <200000000>; power-domains = <&pd IMX_SC_R_SDHC_1>; fsl,tuning-start-tap = <20>; fsl,tuning-step= <2>; status = "disabled"; }; &usdhc2 { assigned-clocks = <&clk IMX_SC_R_SDHC_1 IMX_SC_PM_CLK_PER>; assigned-clock-rates = <200000000>; pinctrl-names = "default", "state_100mhz", "state_200mhz"; pinctrl-0 = <&pinctrl_usdhc2>, <&pinctrl_usdhc2_gpio>; pinctrl-1 = <&pinctrl_usdhc2_100mhz>, <&pinctrl_usdhc2_gpio>; pinctrl-2 = <&pinctrl_usdhc2_200mhz>, <&pinctrl_usdhc2_gpio>; bus-width = <4>; vmmc-supply = <&reg_usdhc2_vmmc>; cd-gpios = <&lsio_gpio4 22 GPIO_ACTIVE_LOW>; wp-gpios = <&lsio_gpio4 21 GPIO_ACTIVE_HIGH>; status = "okay"; };

I am wondering if trace length has something to do with this error. This is because previously I have tried on another board also using iMX8, but the SD card slot is nearer to the processor. In this case, I did not encounter any tuning failure for both SDR50 and SDR104

If trace length is the issue, what parameters I can tweak? Thanks

Re: tuning failed for SDR50

Rita_Wang — Mon, 28 Jul 2025 00:15:11 GMT

How about your usdhc2 hardware design? For the SD card design, for the IO power is 1.8V or 3.3V?

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tuning failed for SDR50

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