User Manual
Secure Digital (SD) Bus Protocol Description
TriFlash with SD Interface Product Manual (Preliminary), Rev. 1.2 © 2002/2003 SANDISK CORPORATION
4-9
Data-transfer
mode
From all states in
data-transfer mode
No state transition
in data-transfer mode
Card Identification
mode
CMD4,
9, 10
CMD12
"operation
complete"
CMD17, 18, 30, 56(r)
ACMD51
CMD24, 25, 26,
27, 42, 56(w)
CMD28,
29, 38
CMD 16, 32...37
ACMD6, 13, 42
ACMD 22,23
CMD3
CMD13, CMD55
CMD7
CMD7
"Operation
complete"
"Operation
complete"
CMD15 CMD0
Sending-data
state (data)
Receive-data
state (rcv)
Disconnect
state (dis)
Programming
state (prg)
Transfer
state (tran)
Stand-by state
(stby)
CMD12 or
"transfer end"
"Operation
complete"
CMD7
CMD7
Figure 4-8. SD Bus State Diagram (Data Transfer Mode)
CMD7 is used to select one TriFlash and place it in the Transfer State. Only one TriFlash or card can be in the
Transfer State at a given time. If a previously selected TriFlash or 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
device address “0x0000,” all devices transfer back to Stand-by State. (Note that it is the responsibility of the Host to
reserve the RCA=0 for device de-selection—refer to Table 4-4, CMD7 description). This may be used before
identifying new devices without resetting other already registered devices. Devices that already have an RCA do not
respond to identification commands (ACMD41, CMD2, CMD3) in this state.
NOTE: The device de-selection is done if a certain device gets CMD7 with un-matched RCA. That happens
automatically if selection is done to another device and the CMD lines are common. So, in the SD bus
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 device de-selection
will be done automatically (as in MultiMediaCard bus system).
• If the CMD lines are separate, to be aware of the necessity to de-select devices.
All data communication in the Data Transfer Mode is point-to point between the host and the selected TriFlash
(using addressed commands). All addressed commands are acknowledged with a response on the CMD line.