STM32H7 UHS cards problem not reaching full speed of W/R 48MBps/65MBps at second debugging session

[Linas L]

Hello,

I made board with STM32H7 and i am running UHS example.

First time i always get 48MBps write and 65MBps read, but at the second debugging i get only 8MBps read/write speed, and i have to remouve card and insert it again to get back to that blistering speed. Any idea why ?

Also, does any one has fatfs working with UHS cards (with 1.8V tranciever)

[Tesla DeLorean]

The board I have with the transceiver has the Z Rev silicon so I'm not entirely sure the SDMMC is working, have other code working on X and Y Rev.

Not entirely sure the code I've seen would negotiate the mode switch properly.

[Linas L]

mine has rev Y.

Just in case will implement power cycle capability for sdcard

[Tesla DeLorean]

I've tried to do DDR on eMMC, and looked at code examples from ST, but wasn't able to make it function. The eMMC permits 3V signalling, and thus doesn't need a transceiver in this context. I've had eMMC solutions clocking at 52 MHz in 8-bit mode. And the parts did report as being DDR 3V capable.