SanDisk SDSDB-32-201-80 - Industrial Grade Flash Memory Card Product Manual page 59

Card Identification
mode
Data-transfer
mode
"Operation "Operation
complete" complete"
Disconnect
state (dis)
CMD7 is used to select one SD Card and place it in the Transfer State. Only one SD Card can be in the Transfer
State at a given time. If a previously selected SD Card is in the Transfer State, its connection with the host is
released and it will move back to the Stand-by State. When CMD7 is issued with the reserved relative card address
"0x0000," all cards transfer back to Stand-by State. (Note that it is the responsibility of the Host to reserve the
RCA=0 for card de-selection—refer to Table 4-3, CMD7 description). This may be used before identifying new
cards without resetting other already registered cards. Cards that already have an RCA do not respond to
identification commands (ACMD41, CMD2, CMD3) in this state.
Important Note: The card de-selection is done if a certain card gets CMD7 with un-matched RCA. That happens
automatically if selection is done to another card and the CMD lines are common. So, in the SD Card system, it will
be the responsibility of the host either:
To work with the common CMD line (after initialization is done). In this case the card de-selection
will be done automatically (as in MultiMediaCard system).
If the CMD lines are separate, to be aware of the necessity to deselect cards.
All data communication in the Data Transfer Mode is point-to point between the host and the selected SD Card
(using addressed commands). All addressed commands are acknowledged with a response on the CMD line.
The relationship between the various data transfer modes is summarized in Figure 4-8, and in the following
paragraphs:
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
CMD3
CMD15
From all states in
data-transfer mode
CMD13, CMD55
No state transition
in data-transfer mode
Stand-by state
(stby)
CMD4,
9, 10
CMD28,
29, 38
CMD7
CMD7
Figure 4-8. SD Card State Diagram (Data Transfer Mode)
Secure Digital (SD) Card Protocol Description
CMD0
Sending-data
state (data)
CMD12
CMD17, 18, 30, 56(r)
"operation
complete"
CMD7
Transfer
CMD7
state (tran)
CMD24, 25, 26,
"Operation
complete"
Receive-data
Programming
state (prg) "transfer end"
ACMD51
CMD 16, 32...37
ACMD6, 13, 42
ACMD 22,23
27, 42, 56(w)
state (rcv)
CMD12 or
4-9