SanDisk SD Card

Revision 2.2Chapter 4 – SD Card Protocol DescriptionSanDisk SD Card Product ManualFigure 4-9Use of Switch CommandCheck Function(Mode=0)CMDCMD6ResDATSwitch FunctionCard internalexecution(Mode=1)Status DataFunction change timing:within 8 clocksCMDCMD6ResDATCard internalexecutionStatus DataCurrent FunctionSwitched FunctionCMD6 supports six function groups, and each function group supports 16 branches(functions). Only one function can be chosen and active in a given function group.Function 0 in each function group is the default function (compatible with v1.01).CMD6 can be used in two modes.• Mode 0—Check Function− Check function is used to query if the card supports a specific function orfunctions• Mode 1—Set Function− Set function is used to switch the functionality of the card.Mode 0 Operation—Check FunctionCMD6 is used in Mode 0 to query which functions the card supports, and to identify themaximum current consumption of the card under the selected functions.A query is accomplished by setting the argument field of the command.1. Set mode bit to 0.2. Select only one function in each function group. Setting the function to 0x0 selectsthe default function. Use appropriate values from Table 4-3 to selecting a specificfunction. Selecting 0xF will keep the current function that was selected for thefunction group.In response to a query, the switch function status will return the following.−−−Functions not supported by each of the function groupsFunction the card will switch to, in each of the function groups. This value isidentical to the provided argument if the host made a valid selection or 0xF if theselected function was invalid.Maximum current consumption under the selected functions. If one of theselected functions was strong the return value will be 0.© 2004 SanDisk Corporation 4-21 12/08/04