Card Identification Mode - SanDisk SDSDB-32-201-80 - Industrial Grade Flash Memory Card Product Manual

Two operation modes are defined for SD Cards:
Card Identification Mode—The host will be in card identification mode after reset and while it is
looking for new cards on the bus. SD Cards will be in this mode after reset until the SEND_RCA
command (CMD3) is received.
Data Transfer Mode—SD Cards will enter data transfer mode once their RCA is first published. The
host will enter data transfer mode after identifying all of the SD Cards on the bus.
Table 4-1 lists the dependencies between operation modes and card states. Each state in the SD Card state diagram
(Figures 4-7 and 4-8) is associated with one operation mode.
Table 4-1. Overview of Card States versus Operation Modes

4.3. Card Identification Mode

While in Card Identification Mode, the host resets all the cards that are in Card Identification Mode, validates
operation voltage range, identifies cards and asks them to publish Relative Card Address (RCA). This operation is
done to each card separately on its own CMD line. All the data communication in the Card Identification Mode uses
only the command line (CMD).
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Card State
Inactive State Inactive
Idle State
Ready State Card Identification Mode
Identification State
Stand-by State
Transfer State
Sending-data State Data Transfer Mode
Receive-data State
Programming State
Disconnect State
Secure Digital (SD) Card Protocol Description
Operation Mode
4-5