STM32's SDMMC1 port for SD card

[MBair.1]

Hi All,

We are using STM's STM32H750VB in our design.

We are planning to STM32's SDMMC1 port for SD card.

We were just wondering what is the maximum capacity/size we can go for SD card or how much max. size the controller can support.

Anybody knowing some number on this ?

Regards,

Madhusoodana Bairy

[TDK · Accepted solution]

The hardware can support any size. I believe the STM32H7 HAL functions can support effectively any size (up to 2TB), although the code is lacking in some areas.

[MBair.1]

Hi TDK,

Thanks for your response and answer. 👍

[Tesla DeLorean]

I've used 400GB cards, but getting into the realm of impractical or costly. As mentioned by TDK 2TB is perhaps the ceiling for 32-bit block addressable 512-byte blocks.

I​ could test larger cards if provided

[MBair.1]

Hi,

One more query on SD voltage level of STM32H750IB part.

The VDD range for STM32H750IB part is mentioned as 1.62 to 3.6 V in the datasheet. So, whether the device is compliant to 1.8V supply too ?

If Yes, whether the SDMMC controller in the MCU supports both SD 2.0 (3.3V) and SD 3.0 (1.8V) ?

Thanks.

[TDK]

The logic level of the bus is dictated by VDD. If you supply 1.8V, that's what it will output. Be aware that running at low voltages comes with drawbacks to execution speed.

[MBair.1]

Thanks TDK for the confirmation.