What support is provided on the BF54x for SD secure digital cards?
The ADSP-BF54x processors' SD interface supports SDHC and SD 2.0 spec. The SW driver is capable of accessing SDHC cards. We have tested against a 4GB card, but they can go up to 32GB at present. High speed mode is supported up to a maximum frequency of operation of 40MHz. Standard speed is supported up to a maximum frequency of 20MHz max. These operating frequencies are included in the rev PrH BF54x datasheet currently posted on the ADI public web site.
To further qualify the above statements – In theory, the SDH driver can handle all sizes of SDHC cards. We have only tested 4GB. The FAT file system is only good for 32GB without extensions. We have no current plans (i.e. scheduled work) to extend the FAT beyond 32GB. Therefore the combination of the SDH and FAT drivers limits the size of SDHC cards to 32GB.
SDH and SD driver is based on SD 2.0 spec and should support all cards designed as per the spec. We haven't come across a non-SD spec compliant card, as the mfrs usually don't disclose it outright. Such cards are not supported by the driver and, I believe, the SDH might not support it as well.
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