IMX8 Mini: run microSD2 without reset pull-up

Alex34 — Wed, 22 Dec 2021 09:25:34 GMT

Hello!

I made a custom board based on IMX8MINI, but unfortunately, I did not pull up the RESET ball of uSD2.

I pulled up only BOOT_CFG[10], and BOOT_CFG[12] (all the rest are left float). BOOT_MODE0 = 0, BOOT_MODE1 = 1. (Internal boot).

There is no activity at uSD2 lines at startup, the voltage at data lines - about 0.8V. (they are pulled-up t 0 3.3V). Also, there is no voltage at the dedicated vdd_uSD2 LDO output of the PMIC. As far as I understand - this is the only LDO that activates by software, but I can't see any activity on i2c lines at startup.

The USB works well, so I'm able to load and execute images, such as u-boot via the uuu tool. While loading SPL and U-boot - no voltage rise at LDO, so uSD2 doesn't work.

So, the questions are:

1. did I configure BOOT_CFG pins correctly?

2. is it mandatory to have an external pull-up on the uSD2_RESET ball?

3. Can I override this setting by PINMUX in the device tree (or somewhere else?)

4. Maybe I can somehow enable the uSD2 interface via u-boot shell?

Re: IMX8 Mini: run microSD2 without reset pull-up

igorpadykov — Wed, 22 Dec 2021 10:44:46 GMT

Hi Alex

1. for BOOT_CFG configuration one can look at p.11 SPF-31399 i.MX8M Mini EVK

schematic i.MX 8M Mini Evaluation Kit DDR4 Design Files

2. it is mandatory as shown on p.6 schematic

3.4. no

Best regards
igor

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IMX8 Mini: run microSD2 without reset pull-up

Re: IMX8 Mini: run microSD2 without reset pull-up