Sdio Read Wait Operation | SDI Technologies SDIO Card specification

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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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SDI Technologies SDIO Card manual Sdio Read Wait Operation

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 Functions Sdio Signaling Definition Sdio Card TypesSdio Card modes Sdio Host Modes Signal Pins Signal connection to two 4-bit Sdio cards Sdio 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 bit Response R4 in SD mode Iosendopcond Response R4 Acceptable Commands after Initialization Recommendations for RCA after ResetSpecial Initialization considerations for Combo Cards Re-initialize both I/O and Memory Re-Initialization Flow for I/O Controller Re-Initialization Flow for Memory controller Enabling 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 States Data Transfer Block Sizes Data Transfer AbortChanges to SD Memory Fixed Registers Read Abort OCR Register CID RegisterCSD Register RCA Register Clear Sdio Status Register StructureBit Identifier Type Value Description New I/O Read/Write Commands Iorwdirect Command CMD52 Comcrcerror IllegalcommandIorwdirect Response R5 1 CMD52 Response SD modes DIS=Disabled Identifier Type Value Description Clear ConditionCMD=DAT lines free TRN=Transfer Iorwextended Command CMD53 Iorw Extended command Op Code DefinitionOP code Command operation CRC Byte Count Values 1 CMD53 Data Transfer Format Register Access Time Sdio Card Internal OperationOverview Interrupts Suspend/Resume Read WaitCMD52 During Data Transfer Sdio Fixed Internal Map Common I/O Area CIA Card Common Control Registers Cccr Card Common Control Registers Cccr TypeCCCR/SDIO IOE3 To abort transfers to/from memory Scsi 4BLS Transaction of function 0 CIA Cccr bit Definitions Empc Function Basic Registers FBR AddressFunction Basic Information Registers FBR Field Type Sdio Simplified Specification Version Field Type FBR bit and field definitions Setting Block Size with CMD53 Card Information Structure CISMultiple Function Sdio Cards Card Information Structure CIS and reserved area of CIA Bus State Diagram State Diagram for Bus State Machine Embedded I/O Code Storage Area CSA CSA AccessCSA Data Format Sdio Interrupts Interrupt Timing Terminated Data Transfer Interrupt Cycle Interrupt Clear Timing Sdio Suspend/Resume Operation Sdio Read Wait Operation Power Control Power Control OverviewPower Control support for Sdio Cards Master Power Control Power Control Support for the Sdio Host Power SelectionHigh-Power Tuples Reference Tuples by Master Power Control and Power Select Power Control Operation Sdio High-Speed Mode High-Speed ModeSwitching Bus Speed Mode in a Combo Card Sdio Power Sdio Physical Properties Sdio Simplified Specification Version Inrush Current Limiting CIS Formats CIS Reference DocumentBasic Tuple Format and Tuple Chain Structure Byte Order Within Tuples Tuple Version Sdio Card MetaformatTuples Supported by Sdio Cards Code Name Description Cistplmanfid Manufacturer Identification String Tuple Sdio Specific ExtensionsCistplmanfid Manufacturer Identification Tuple Cistplfuncid Function Identification Tuple Cistplfunce Function Extension Tuple Cistplfunce Tuple General StructureCistplfunce Tuple for Function 0 common Tplfidfunction Tuple for Function 0 common Tplfidfunction Tuple for Function Cistplfunce Tuple for FunctionByte Sdio Simplified Specification Version Tplfidfunction Field Descriptions for Functions 10 Tplfefunctioninfo Definition11 Tplfecsaproperty Definition Bit Name Cistplsdiostd Function is a Standard Sdio Function 12 Cistplsdiostd Tuple Reserved for Sdio CardsCistplsdioext Tuple Reserved for Sdio Cards 13 Cistplsdioext Tuple Reserved for Sdio Cards Table A-14 SD Mode Command List SD and SPI Command ListNormative Table A-15 SPI Mode Command List Sdmem Sdio Appendix B Normative References Appendix C Abbreviations and Terms LOW, High Informative