STM32H743 (I/O direction control of SDMMC CMD signal)

[MSugi.1]

I'm thinking of getting STM32H743 to work Wi-Fi module via uSD.

However since I can not get my Wi-Fi module responding I start questioning my design.

SDMMC POWER.DIPOL control but can change the polarity of CIDR, D0DIR, D123DIR,

Is there a way to change this bit individually?

Thanks in advance.

Sugino​

[TDK]

> SDMMC POWER.DIPOL control but can change the polarity of CIDR, D0DIR, D123DIR,

Is there a way to change this bit individually?

This isn't written very clearly, but I am going to assume you want to change the polarity of CDIR while keeping the polarity of D0DIR, D123DIR alone.

DIRPOL affects all of the signals. Why do you want to control the polarity of CDIR separately from the rest?

Those signals are outputs, not inputs. The direction of each line is governed by the internal state machine and those signals are provided as inputs for a level shifter.

[MSugi.1]

I'm sorry

I want to control H / L individually, not polarity.

Is that possible?

[TDK]

Still not clear what you're asking.

You want to bit bang the CMD signal?

[MSugi.1]

Hi,

Using the code generated by Cubemx, you are trying to work with the Wi-Fi module via USD

Since I failed with the SDIO initialization function, I found that the I/O direction of the CDIR when sending CMD was reversed as a result of investigation.

Similarly, I think that SDMMC_D signals are reversed, so I want to control individually.

[TDK]

You can't change the direction of lines just because you think they're wrong. The lines are governed by the internal hardware state machine of the peripheral, which works. Perhaps revisit your assumptions on why you think it's wrong, post evidence, etc.

[Tesla DeLorean]

I guess the inference is the buffer is wired backwards.

The transceiver should only be needed for low voltage cards. ​