how to set SD2 pins voltage as 1.8v

[xrztech_wen]

hi,everyone,

      I want to set these pins voltage as 1,8v on  i.MX6SoloLite:

• SD2_CLK
• SD2_CMD
• SD2_DAT0
• SD2_DAT1
• SD2_DAT2
• SD2_DAT3

  These pins were connect to SDIO card,so we need init these pins as:

	MX6SL_PAD_SD2_CLK__USDHC2_CLK_50MHZ,
	MX6SL_PAD_SD2_CMD__USDHC2_CMD_50MHZ,
	MX6SL_PAD_SD2_DAT0__USDHC2_DAT0_50MHZ,
	MX6SL_PAD_SD2_DAT1__USDHC2_DAT1_50MHZ,
	MX6SL_PAD_SD2_DAT2__USDHC2_DAT2_50MHZ,
	MX6SL_PAD_SD2_DAT3__USDHC2_DAT3_50MHZ,

then I call below funtion to set these pins voltage:

int mx6sl_setSDIOCardVoltage(void)

{

  mxc_iomux_set_specialbits_register(MX6SL_PAD_SD2_CLK,

  PAD_CTL_LVE, PAD_CTL_LVE_MASK);

  mxc_iomux_set_specialbits_register(MX6SL_PAD_SD2_CMD,

  PAD_CTL_LVE, PAD_CTL_LVE_MASK);

  mxc_iomux_set_specialbits_register(MX6SL_PAD_SD2_DAT0,

  PAD_CTL_LVE, PAD_CTL_LVE_MASK);

  mxc_iomux_set_specialbits_register(MX6SL_PAD_SD2_DAT1,

  PAD_CTL_LVE, PAD_CTL_LVE_MASK);

  mxc_iomux_set_specialbits_register(MX6SL_PAD_SD2_DAT2,

  PAD_CTL_LVE, PAD_CTL_LVE_MASK);

  mxc_iomux_set_specialbits_register(MX6SL_PAD_SD2_DAT3,

  PAD_CTL_LVE, PAD_CTL_LVE_MASK);

return 0;

}

but after complied,the voltage still is 3.3v.

Can you help me to check where was wrong?  How to solve this problem?

Thanks very much!

[igorpadykov · Accepted solution]

Hi wen

SD card voltage select  can be accomplished by

setting VSELECT bit in uSDHCx_VEND_SPEC register.

Attached is code example to force 1.8V voltage at uSDHC3 port on i.MX6SLEVK

board. It is based on L3.10.17_1.0.0_GA. You may follow the it and set other uSDHC port to 1.8V as well.

Please notice that merely making software change is not enough. Your

hardware must also follow the section "Power-up sequence in low power voltage

system design" in the document "Hardware Development Guide for

i.MX 6SoloLite - User Guide". The document is available at i.MX6SL|i.MX 6SoloLite

Processors|Wearables|Freescale

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=IMX6SLEVK&fpsp=1&tab=Documentation_Ta...

Best regards

igor

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