SDI Technologies SDIO Card manual Sdio Read Wait Operation

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©Copyright 2000-2007 SD Card Association

SDIO Simplified Specification Version 2.00

10. SDIO Read Wait Operation

The optional Read Wait (RW) operation is defined only for the SD 1-bit and 4-bit modes. The read Wait operation allows a host to signal a card that is executing a read multiple (CMD53) operation to temporarily stall the data transfer while allowing the host to send commands to any function within the SDIO card. To determine if a card supports the Read Wait protocol, the host shall test SRW capability bit in the Card Capability byte of the CCCR (see Table 6-1). The timing for Read Wait is based on the Interrupt Period that is defined in section 8.1

If a card does not support the Read Wait protocol, the only means a host has to stall (not abort) data in the middle of a read multiple command is to control the SDCLK. Read wait support is mandatory for the card to support suspend/resume.

The rest of this chapter is not included in the Simplified Specification.

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Contents SD Specifications Part E1 Sdio Simplified Specification Changes compared to previous issue Sdio Simplified Specification VersionDate Version Release of SD Simplified Specification Conventions Used in This Document Table of Contents SPI and SD 1-bit Mode Interrupts 16.2 Table of Tables Table of Figures Sdio Features General DescriptionPrimary Reference Document Standard Sdio FunctionsSdio Signaling Definition Sdio Card TypesSdio Card modes Sdio Host ModesSignal Pins Signal connection to two 4-bit Sdio cardsSdio Card Initialization ResetDifferences in I/O card Initialization Sdio Simplified Specification Version MEM=0 Card initialization flow in SD mode Sdio aware host Illegal Command F8=0 Card initialization flow in SPI mode Sdio aware host Iosendopcond Command CMD5 VDD Voltage Window PositionOCR Values for CMD5 OCR bitResponse R4 in SD mode Iosendopcond Response R4Acceptable Commands after Initialization Recommendations for RCA after ResetSpecial Initialization considerations for Combo Cards Re-initialize both I/O and MemoryRe-Initialization Flow for I/O Controller Re-Initialization Flow for Memory controllerEnabling CRC in SPI Combo Card Sdio Command List Differences with SD Memory SpecificationUnsupported SD Memory Commands Modified R6 Response Reset for SdioBus Width Card Detect Resistor TimingsCombo Card 4-bit Control Card Detect Resistor StatesData Transfer Block Sizes Data Transfer AbortChanges to SD Memory Fixed Registers Read AbortOCR Register CID RegisterCSD Register RCA RegisterClear Sdio Status Register StructureBit Identifier Type Value Description New I/O Read/Write Commands Iorwdirect Command CMD52Comcrcerror IllegalcommandIorwdirect Response R5 1 CMD52 Response SD modesDIS=Disabled Identifier Type Value Description Clear ConditionCMD=DAT lines free TRN=TransferIorwextended Command CMD53 Iorw Extended command Op Code DefinitionOP code Command operation CRCByte Count Values 1 CMD53 Data Transfer FormatRegister Access Time Sdio Card Internal OperationOverview InterruptsSuspend/Resume Read WaitCMD52 During Data Transfer Sdio Fixed Internal MapCommon I/O Area CIA Card Common Control Registers CccrCard Common Control Registers Cccr TypeCCCR/SDIO IOE3To abort transfers to/from memory Scsi 4BLS Transaction of function 0 CIA Cccr bit Definitions EmpcFunction Basic Registers FBR AddressFunction Basic Information Registers FBR Field TypeSdio Simplified Specification Version Field Type FBR bit and field definitionsSetting Block Size with CMD53 Card Information Structure CISMultiple Function Sdio Cards Card Information Structure CIS and reserved area of CIABus State Diagram State Diagram for Bus State MachineEmbedded I/O Code Storage Area CSA CSA AccessCSA Data Format Sdio Interrupts Interrupt TimingTerminated Data Transfer Interrupt Cycle Interrupt Clear TimingSdio Suspend/Resume Operation Sdio Read Wait Operation Power Control Power Control OverviewPower Control support for Sdio Cards Master Power ControlPower Control Support for the Sdio Host Power SelectionHigh-Power Tuples Reference Tuples by Master Power Control and Power SelectPower Control Operation Sdio High-Speed Mode High-Speed ModeSwitching Bus Speed Mode in a Combo Card Sdio Power Sdio Physical PropertiesSdio Simplified Specification Version Inrush Current Limiting CIS Formats CIS Reference DocumentBasic Tuple Format and Tuple Chain Structure Byte Order Within TuplesTuple Version Sdio Card MetaformatTuples Supported by Sdio Cards Code Name DescriptionCistplmanfid Manufacturer Identification String Tuple Sdio Specific ExtensionsCistplmanfid Manufacturer Identification Tuple Cistplfuncid Function Identification TupleCistplfunce Function Extension Tuple Cistplfunce Tuple General StructureCistplfunce Tuple for Function 0 common Tplfidfunction Tuple for Function 0 commonTplfidfunction Tuple for Function Cistplfunce Tuple for FunctionByte Sdio Simplified Specification Version Tplfidfunction Field Descriptions for Functions 10 Tplfefunctioninfo Definition11 Tplfecsaproperty Definition Bit NameCistplsdiostd Function is a Standard Sdio Function 12 Cistplsdiostd Tuple Reserved for Sdio CardsCistplsdioext Tuple Reserved for Sdio Cards 13 Cistplsdioext Tuple Reserved for Sdio CardsTable A-14 SD Mode Command List SD and SPI Command ListNormative Table A-15 SPI Mode Command List Sdmem SdioAppendix B Normative ReferencesAppendix C Abbreviations and TermsLOW, High Informative