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SDIO Simplified Specification Version 2.00
Field | Type | Description |
Bus Width | R/W | Defines the data bus width |
1:0 |
| |
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| support of |
CD Disable | R/W | Connect[0]/Disconnect[1] the |
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| the card. The |
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| |
SCSI | R/O | Support Continuous SPI interrupt. This |
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| card supports the assertion of interrupts in the SPI mode at any time, irrespective of |
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| the status of the card select (CS) line. If this bit is zero, then this SDIO card can only |
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| assert the interrupt line in the SPI mode when the CS line is asserted. This bit signals |
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| the capability of all functions in the SDIO card. |
ECSI | R/W | Enable Continuous SPI Interrupt. If the SCSI bit is set, then this R/W bit is used to |
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| allow the SDIO card to assert the interrupt line in the SPI mode at any time, |
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| irrespective of the state of the CS line. This bit is cleared to zero on reset or |
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| If the SCSI bit is clear, this bit shall be read only and set to zero. This bit controls the |
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| assertion of interrupts in the SPI mode for all functions in the SDIO card. |
SDC | R/O | Card Supports Direct Commands during data transfer. This bit applies only to the SD |
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| modes, it does not apply to SPI mode. This flag bit reports the SDIO card’s ability to |
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| execute CMD52 while data transfer is in progress. If this bit is set, all I/O functions |
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| shall accept and execute the CMD52 while data transfer is underway on the DAT[x] |
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| lines. Also, any memory in a combo card shall allow the CMD52 to execute while it is |
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| transferring data. Since the CMD52 does not use the DAT[x] lines, it is possible to |
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| execute while data transfer to a different address on the card is underway. CMD52 is |
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| described in 5.1. In any case, SD or SPI mode, if an error occurs during data transfer |
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| the SDIO card shall accept CMD52 to allow I/O abort and reset regardless of this bit |
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| value. If the card supports suspend/resume then it shall also support this bit. |
SMB | R/O | Card Supports |
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| IO_RW_EXTENDED command (CMD53) in the block mode. If this bit is set, all I/O |
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| functions |
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| The IO_RW_EXTENDED command is described in 5.3 |
SRW | R/O | Card Supports Read Wait. This bit applies only to the SD modes, it does not apply to |
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| SPI mode. This flag bit reports the SDIO card’s ability to support the Read Wait |
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| Control (RWC) operation. If set, all functions on the card are able to accept the wait |
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| signal on DAT[2]. RWC operation is described in section 6.5. Any card that supports |
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| Suspend/Resume shall also support Read Wait |
SBS | R/O | Card supports Suspend/Resume. This bit applies only to the SD modes, it does not |
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| apply to SPI mode. This flag bit reports the SDIO card’s ability to Suspend and |
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| Resume operations at the request of the host. If this bit is set, all functions except 0 |
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| shall accept a request to suspend operations and resume under host control. |
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| Suspend/Resume operation is described in 6.4. If this bit is 0, registers |
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| shall not be supported. |
S4MI | R/O | Supports interrupt between blocks of data in |
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| SDIO card’s ability to generate interrupts during a |
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| this bit is 0, then the SDIO card is not able to signal an interrupt during a |
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| data transfer in |
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| data transfer is complete. If this bit is 1, then the SDIO card is able to signal an |
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| interrupt between blocks while data transfer is in progress. This operation is |
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| described in 8.1.4 Note, even if a card does not support the interrupt during |
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| block transfer (S4MI=0), the card may signal interrupts during all other Interrupt |
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| Periods while the interrupt is enabled (IENx=1). |
31
