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MultiMediaCard Product Manual
4.3.1
Power Protection
Same as for MultiMediaCard mode.
4.4
Electrical Interface
4.4.1
Power-up
The power up of the MultiMediaCard bus is handled locally in each MultiMediaCard and in the bus
master.
After power-up (including hot insertion, that is,
inserting a card when the bus is operating), t h e
MultiMediaCard enters the Idle State. During
this state, the MultiMediaCard ignores all bus
transactions until CMD1 is received.
CMD1 is a special synchronization command used
to negotiate the operation voltage range and to
poll the cards until they are out of their power-up
22
Figure 4-3 Power-up Diagram
sequence. Besides the operation voltage profile of
the cards, the response to CMD1 contains a busy
flag, indicating that the card is still working on
its power-up procedure and is not ready for
identification. This bit informs the host that a t
least one card is not ready. The host has to wait
(and continue to poll the cards) until this bit is
cleared.
SanDisk MultiMediaCard Product Manual Rev. 2 © 2000 SANDISK CORPORATION
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