MultiMediaCardTM
Read
The read access time is defined as the sum of the two times given by the CSD parameters TAAC and
NSAC (refer to Table “Card Specific Data (CSD)”). These card parameters define the typical delay
between the end bit of the read command and the start bit of the data block. This number is card
dependent and should be used by the host to calculate throughput and the maximal frequency for
stream read.
Write
The R2W_FACTOR field in the CSD is used to calculate the typical block program time obtained by
multiplying the read access time by this factor. It applies to all write/erase commands (e.g.
SET(CLEAR)_WRITE_PROTECT, PROGRAM_CSD(CID) and the block write commands). It should
be used by the host to calculate throughput.
Erase
The duration of an erase command will be (order of magnitude) the number of sectors to be erased
multiplied by the block write delay.
4.8 Card Identification Mode
All the data communication in the card identification mode uses only the command line (CMD).
MultiMediaCard State Diagram (Card Identification Mode)
Figure 4-2 MultiMediaCard State Diagram (Card Identification Mode)
The host starts the card identification process in open drain mode with the identification clock rate fOD
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