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Bart
Joined: 12 Jul 2005 Posts: 49
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Difference between 3,3 V MMC and dual (1,8/3,0) volt MMC ? |
Posted: Tue Dec 13, 2005 4:14 pm |
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Does someone know if there is a difference in the SPI initialising of both MMC ?
It seems I can initialize the real MMC ( on 3,3 volt) cards (tested with a 8 MB and a 32 MB) but not the dual volt MMC (62MB Nokia)
Aren't the dual volt MMC's not fully compatible with the 3,3 volt cards ?
Thanks for the reply's _________________ I like Skype (www.skype.com), my username is BplotM |
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asmallri
Joined: 12 Aug 2004 Posts: 1634 Location: Perth, Australia
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Posted: Tue Dec 13, 2005 7:16 pm |
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Yuu can download the spec for free at: http://www.mmca.org/compliance/buy_spec/MMCA_System_SummaryV41.pdf
The cards present a bit map corresponding to the voltage ranges they operate over. A host during initialization, specifies the range it is operating at using the bit map. If the card is not happy it disconnects.
I have tested cards from about 10 different manufacturers and have not had to do this yet. _________________ Regards, Andrew
http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!! |
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