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???
09/28/09 07:36
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 		 #169213 - How fast?
Responding to: ???'s previous message
Richard Erlacher said:
has anybody succeeded in implementing an SD-card (not MMC!) in SD-mode with the full-speed 4-bit-wide interface

What do you mean by "full" speed here?

SD Cards come in various speed classes: http://www.sdcard.org/developers/tech/speed_class/

Then, I s'pose there's a second issue: how much of the 8051's CPU time can you afford it to spend on this?
If it can achieve the IO speed to the card, but that takes 100% of the CPU time, then I guess that won't be terribly useful - will it?

Perhaps you'd like to raise an order for me to spend, say, a week looking into this and report back to you...?
(I think the current state of the pound vs the dollar is in your favour at the moment...)

List of 55 messages in thread
TopicAuthorDate
I've asked this before ... but ...            01/01/70 00:00      
   Is this specifically 8051?            01/01/70 00:00      
      specifically with 805x and NO SD-specific hardware on-chip            01/01/70 00:00      
         There often are huge speed differences            01/01/70 00:00      
   Yep I have            01/01/70 00:00      
      I'd be interested in that ...            01/01/70 00:00      
         Ill send you a schematic            01/01/70 00:00      
            What do points mean?            01/01/70 00:00      
            Well, I haven't seen it ... yet            01/01/70 00:00      
               Oh dear; I hope this wasn't Jez, then...            01/01/70 00:00      
   How fast?            01/01/70 00:00      
      I'm using an old, but relatively complete, spec            01/01/70 00:00      
         "external" hardware            01/01/70 00:00      
            Yes, that would be nice ...            01/01/70 00:00      
         50MBps            01/01/70 00:00      
            That's what the capital B means ...            01/01/70 00:00      
               You assume too much            01/01/70 00:00      
                  It's like that other nomenclature issue I keep mentioning            01/01/70 00:00      
                     Sad, but true            01/01/70 00:00      
               25MHz * 4bit = 12.5MB/s            01/01/70 00:00      
                  correct            01/01/70 00:00      
                  Now I'm confused ... as you can see ...            01/01/70 00:00      
                     someplace to put spec's            01/01/70 00:00      
                        It's a two-edged sword            01/01/70 00:00      
                           True, but..            01/01/70 00:00      
                              Published spec's are in the public domain            01/01/70 00:00      
                                 No, that's not true            01/01/70 00:00      
                                    It depends on how the IP is used, doesn't it?            01/01/70 00:00      
                                       No, it doesn't.            01/01/70 00:00      
                                          Not public domain            01/01/70 00:00      
                                             Quite so!            01/01/70 00:00      
                                             Copyright Term and the Public Domain in the United States            01/01/70 00:00      
                                                They have the "right" but not the cause            01/01/70 00:00      
                                                   Letter of the law            01/01/70 00:00      
                                                      Let me ask you something ...            01/01/70 00:00      
                                                         I didn't say that            01/01/70 00:00      
                                                   They have the right            01/01/70 00:00      
                                                      When was the last time you saw a written copyright?            01/01/70 00:00      
                                                         See previous examples!            01/01/70 00:00      
                                                            Whose interests are "protected"?            01/01/70 00:00      
                                                               Information owners            01/01/70 00:00      
                                                                  ?            01/01/70 00:00      
                                                                     Life isn't fair            01/01/70 00:00      
                                                               What the thread is about? SD Card or CopyRights!!!            01/01/70 00:00      
                                                                  There's a reason for that ...            01/01/70 00:00      
                                                                     Lots of interests in SD, but danger involved in sharing            01/01/70 00:00      
                                                         last time I saw a written copyright ...            01/01/70 00:00      
                                                            No need for long legalese            01/01/70 00:00      
                                                               True, but ...            01/01/70 00:00      
                                                            That's the boilerplate to which I referred            01/01/70 00:00      
                                                               the band won            01/01/70 00:00      
                                                      Ooops!            01/01/70 00:00      
   I forgot sorry            01/01/70 00:00      
      That was what ... 6 weeks ago?            01/01/70 00:00      
   SD/SDIO host controller chips            01/01/70 00:00      

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