SanDisk SD Card
SanDisk SD Card
SanDisk SD Card
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
Revision 2.2Chapter 4 – <strong>SD</strong> <strong>Card</strong> Protocol Description<strong>SanDisk</strong> <strong>SD</strong> <strong>Card</strong> Product Manual4.2 Functional DescriptionThe host (master) controls all communication between it and the <strong>SD</strong> <strong>Card</strong>. The host sendsthe following two types of commands:• Broadcast Commands— Broadcast commands are intended for all <strong>SD</strong> cards. Some ofthese commands require a response.• Addressed (Point-to-Point) Commands— The addressed commands are sent to theaddressed <strong>SD</strong> <strong>Card</strong> and cause a response to be sent from this card.A general overview of the command flow is shown in Figure 4-7 for the <strong>Card</strong> IdentificationMode and in Figure 4-8 for the Data Transfer Mode. The commands are listed in Tables 4-15 and 4-16. The dependencies among the current <strong>SD</strong> <strong>Card</strong>, received-command andfollowing states are listed in Table 4-18. In the following sections, the various cardoperation modes will be described first. Thereafter, the restrictions for controlling the clocksignal are defined. All <strong>SD</strong> <strong>Card</strong> commands, together with corresponding responses, statetransitions, error conditions, and timings are presented in the following sections.The <strong>SanDisk</strong> <strong>SD</strong> <strong>Card</strong> has two operation modes.• <strong>Card</strong> Identification Mode— The host will be in card identification mode after resetand while it is looking for new cards on the bus. <strong>SD</strong> cards will be in this mode afterreset until the SET_RCA command (CMD3) is received.• Data Transfer Mode— <strong>SD</strong> cards will enter data-transfer mode when their RCA is firstpublished. The host will enter data-transfer mode after identifying all <strong>SD</strong> cards on thebus.Table 4-1 lists the dependencies between operation modes and card states. Each state in thecard state diagrams (Figure 4-7 and 4-8) is associated with one operation mode.Table 4-1<strong>Card</strong> States vs. Operation Modes OverviewInactive<strong>Card</strong> StateInactiveOperation ModeIdle, Ready, Identification<strong>Card</strong> Identification ModeStandby, Transfer, Send data, Receive data,Programming, DisconnectData Transfer Mode4.3 <strong>Card</strong> Identification ModeIn <strong>Card</strong> Identification Mode the host resets all cards, validates operation voltage range,identifies and requests cards to publish a Relative <strong>Card</strong> Address (RCA). This operation isperformed on each card separately using its own command (CMD) line. All datacommunication in the <strong>Card</strong> Identification Mode uses the CMD line only.© 2004 <strong>SanDisk</strong> Corporation 4-4 12/08/04
Change language