XU4 UHS-1

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XU4 UHS-1

Post by jeffrey-yzj »

we want to switch sd to UHS-1 mode,so I need to switch sd voltage to 1.8V.
first, I want to know if xu4 can switch sd voltage to 1.8V with u-boot or kernel and how can I achieve it.
thanks for your great help.

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Re: XU4 UHS-1

Post by odroid »

If you use our XU4 Ubuntu OS image, the built-in Kernel(4.14 or 5.4) uses the UHS mode by default and the interface voltage must be 1.8Volt.
If you have a DMM or oscilloscope, measure the interface voltage by yourself.

As far as I know, the stock uboot doesn't use the UHS mode though.

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Re: XU4 UHS-1

Post by jeffrey-yzj »

I use XU4 ubuntu-18.04.3-4.14-minimal-odroid-xu4-20190910 ,but I Use a multimeter to measure the voltage of the SD card is 2.8V. This is why?

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Re: XU4 UHS-1

Post by jeffrey-yzj »

odroid wrote:
Fri Dec 18, 2020 4:30 pm
If you use our XU4 Ubuntu OS image, the built-in Kernel(4.14 or 5.4) uses the UHS mode by default and the interface voltage must be 1.8Volt.
If you have a DMM or oscilloscope, measure the interface voltage by yourself.

As far as I know, the stock uboot doesn't use the UHS mode though.
I use XU4 ubuntu-18.04.3-4.14-minimal-odroid-xu4-20190910 ,but I Use a multimeter to measure the voltage of the SD card is 2.8V. This is why?

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Re: XU4 UHS-1

Post by odroid »

VDD_SD must be always 2.8Volt while the interface voltage could be switched between 1.8Volt and 2.8Volt.
Check D0~D3 and CMD/CLK interface signals with an oscilloscope.

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Re: XU4 UHS-1

Post by jeffrey-yzj »

odroid wrote:
Fri Dec 18, 2020 5:13 pm
VDD_SD must be always 2.8Volt while the interface voltage could be switched between 1.8Volt and 2.8Volt.
Check D0~D3 and CMD/CLK interface signals with an oscilloscope.
Now,I want to add a regulator driver for the SD with u-boot ,Have you dealt with similar case ?
Thanks for your great help.

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Re: XU4 UHS-1

Post by odroid »

Did you check the interface voltage level? What was the actually measured voltage while booting the Linux kernel?

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Re: XU4 UHS-1

Post by jeffrey-yzj »

odroid wrote:
Mon Dec 21, 2020 2:24 pm
Did you check the interface voltage level? What was the actually measured voltage while booting the Linux kernel?
Yes,I measured the voltage of D0 is 1.8V while booting with linux kernel, so I want to add a regulator driver in u-boot.But I can't understand how regulator driver works in linux kernel.

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Re: XU4 UHS-1

Post by odroid »

Thank you for the confirmation.
I have no idea how to port the PMIC driver into uboot but there must be (partially) a PMIC driver in uboot too.
I think you might need to search kernel/uboot source code with PMIC part number "S2MPS11B".

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Re: XU4 UHS-1

Post by jeffrey-yzj »

odroid wrote:
Mon Dec 21, 2020 2:45 pm
Thank you for the confirmation.
I have no idea how to port the PMIC driver into uboot but there must be (partially) a PMIC driver in uboot too.
I think you might need to search kernel/uboot source code with PMIC part number "S2MPS11B".
Thanks for your guidance.I will get a try.

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Re: XU4 UHS-1

Post by jeffrey-yzj »

odroid wrote:
Mon Dec 21, 2020 2:45 pm
Thank you for the confirmation.
I have no idea how to port the PMIC driver into uboot but there must be (partially) a PMIC driver in uboot too.
I think you might need to search kernel/uboot source code with PMIC part number "S2MPS11B".
hello odroid, Now I find there is some driver for SD UHS mode in uboot2020,I want to try if I can achieve the effect I expect.
If xu4 is supports uboot2020? And I should how to make config for uboot2020 ,example uboot2017 is make config by "make odroid-xu4_defconfig" .
thanks for your great help.

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Re: XU4 UHS-1

Post by odroid »

I don't think the upstream uboot supports the XU4 board out of the box.
You probably need to edit some codes and configuration files.

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