2

I am interfacing SD cards (1/2GB SD cards and 4GB SDHC cards from different manufactures) to a custom board in SPI mode and I am using a FATfs file system from elm-chan. I am able to write files and read files on the SD card. However I would like to know where can I get the information on the maximum clock frequency (I can drive my SPI bus) for the given SD card. I have seen that for some SD cards maximum speed was about 1.33MHz and for some 20MHz. I assumed this speed was in the CSD register (TAAC value, as the TRAN_SPEED was the same on all the cards set at 25Mhz). However I realized its not true. I would really appreciate if someone can share their knowledge on this. Thanks!

4

1 回答 1

0

没有明确的 SD 卡部件号，是不可行的。只有当您可以分享确切的细节时，获得正确答案的可能性才会很高。我建议您彻底检查相应 SD 卡的规格以获得快速答案。您能否确认您所做的观察是否与规范中提供的信息不同？

于 2014-09-22T17:27:21.167 回答