We are developing a new product using STM32F767 processor, with a microSD card for storing data. Page 1472 of the Reference Manual (RM0410) contains a description of the SDMMC data length register (SDMMC_DLEN). There is a cryptic note on this page that reads:
For an SDMMC multibyte transfer the value in the data length register must be between 1 and 512.
I am trying to understand the meaning of this sentence. I have found that we can read up to 262144 bytes per transfer when reading from the SD card. This corresponds to 512 sectors. I don't understand why we cannot read more than 262144 bytes per transfer, but am wondering if it is related to the note above. I would appreciate any help on this question.