Messages in this thread | | | Date | Fri, 01 Sep 2006 17:53:59 +0200 | From | Pierre Ossman <> | Subject | Re: SDIO card support in Linux |
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Ian Stirling wrote: >> >> SD mandates a star topology (just a single card per bus), so we'll just >> force a single card into the list. SD memory cards can actually work on >> a shared bus, SDIO can not. It's not a big problem in practice though. > > Is this true in SD-1 bit mode, or SPI?
Yes, no. :)
> I see nothing on a quick read-through of the abbreviated SDIO spec > precluding this. > Of course, it'd mean wire-or'd interrupt lines. >
The problem is that there is no "king-of-the-hill" mechanism in the SDIO init sequence (like there is in SD mem). The protocol assumes that the desired card always receives the command.
Rgds Pierre
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