SanDisk SD Card

Revision 2.2Chapter 4 – SD Card Protocol DescriptionSanDisk SD Card Product ManualCMD Index Type Argument Resp. Abbreviation DescriptionCMD57Application-Specific CommandsAll future reserved commands will have a codeword length of 48 bits, as well as theirresponses (if there are any).The following table describes all application-specific commands supported or reserved bythe SD Card. All the following ACMDs will be preceded with the APP_CMD command(CMD55).Table 4-17Application-specific CommandsACMD Index Type Argument Resp. Abbreviation Command DescriptionACMD6 ac [31:2] stuffbits [1:0]bus widthACMD13 adtc [31:0] stuffbitsR1 SET_BUS_WIDTH Defines the data buswidth (’00’=1bit or’10’=4bits bus) to be used fordata transfer. Theallowed data bus widthsare given in SCR register.R1 SD_STATUS Send the SD MemoryCard status.ACMD17ReservedACMD18 --- --- --- --- Reserved for SD securityapplications. 26ACMD19 toACMD21ReservedACMD22 adtc [31:0] stuffbitsR1 SEND_NUM_WR_BLOCKS Send the number of thewritten (without errors)write blocks. Respondswith 32bit+CRC datablock. IfWRITE_BL_PARTIAL='0',the unit of ACMD22 isalways 512byte. IfWRITE_BL_PARTIAL='1',the unit of ACMD22 is ablock length which wasused when the writecommand was executed.ACMD24ReservedACMD25 --- --- --- --- Reserved for SD securityapplications.ACMD26 --- --- --- --- Reserved for SD securityapplications.ACMD38 --- --- --- --- Reserved for SD securityapplications.ACMD39 toACMD40ReservedACMD41 bcr [31:0]OCRw/out busyR3 SD_SEND_OP_COND Asks the accessed cardto send its operatingcondition register (OCR)content in the responseon the CMD line.26 Refer to “SD Memory Card Security Specification” for detailed explanation about the SD Security Features.© 2004 SanDisk Corporation 4-37 12/08/04