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9 years, 7 months ago.
CMD6 and 50Mhz SPI option
Great job, very clean and follows the specifications nicely. It would be even a greater improvement if the code checked high speed ability and set the HS mode (50Mhz SPI limit) during initialization by using CMD6 IAW the Simplified SD Specifications. Section 7 in the latest SD spec says the HS mode is the same in SPI as in SD and sends you to section 4 for information. Any chance to see that implemented?
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9 years, 7 months ago.
I wasn't aware that 50MHz was allowed in SPI mode. I'll look into this. Thanks for the tip!
It is interesting that SanDisk SD card Product Manual version 2.2 from 2004 section 4.4.9 and figure 4-12 gives a better explanation than even the latest Simplified SD Specification. It also discusses the topology concerns of both frequency and mode change (number of cards allowed on the SPI bus) and other stuff omitted from the SD specification. Recommend you check it out and let me know if you can't find it online.
posted by 20 Sep 2014Small update: I looked into high speed mode earlier this week, and it looks like it might not offer much of a performance improvement in SPI mode. That's not to say I won't add support for it, but I'm pretty slammed at work right now so I won't be able to work on it anytime soon.
posted by 27 Sep 2014Assigned to 9 years, 7 months ago.
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