©Copyright
SDIO Simplified Specification Version 2.00
Field | Type | Description |
E4MI | R/W | Enable interrupt between blocks of data in |
|
| during |
|
| interrupts during a |
|
| interrupts during 4 bit |
|
| does not support 4 bit |
|
| always read as 0. This bit shall be cleared to 0 by any reset |
LSC | R/O | Card is a |
|
| |
4BLS | R/O | |
|
| and it supports |
|
| |
Pointer to | R/O | This |
card’s |
| contains information relation to the entire card. The card common CIS shall be |
common CIS |
| located within the CIS space of function 0 (0x001000- 0x017FFF) as described in |
|
| section 6.11. A card common CIS is mandatory for all SDIO cards. This pointer is |
|
| stored in |
BS | R/O | Bus status: If this bit is set to 1, then the currently addressed function (selected by |
|
| FSx or by the function number in an I/O command) is currently executing a command |
|
| which transfers data on the DAT[x] line(s). If this bit is 0, then the addressed function |
|
| is not using the data bus. This bit is used by the host to determine which function of a |
|
| |
|
| a part of the optional Suspend/Resume protocol. If the card does not support |
|
| Suspend/Resume, this bit shall be read as 0. Any access to the CIA may not be |
|
| suspended, so in this case, BS shall always be set to 1, irrespective of the host |
|
| setting BR to 1. |
BR | R/W | Bus Release Request/Status: This bit is used to request that the addressed function |
|
| (selected by FSx or by the function number in CMD53 or Memory commands using |
|
| DAT line) release the Data lines and suspend operation. If the host sets this bit to 1, |
|
| the addressed function shall temporarily halt data transfer on the DAT[x] lines and |
|
| suspend the command that is in process. The BR bit shall remain set to 1 until the |
|
| release is complete. If the card can never accept the suspend request while |
|
| executing transactions, the card shall return response with BR cleared to 0 and BS |
|
| set to 1. This indicates that the suspend request is cancelled by the card and thus the |
|
| host should not issue a cancel suspend command. |
|
| The followings are the cases where the card can cancel a suspend request: |
|
| Transaction addressed to function 0. |
|
| The card knows the transfer will terminate soon. |
|
| The card knows the transfer is timing critical (i.e. If suspended, the transfer cannot |
|
| proceed). |
|
| A Multi function card that indicates SBS=1, but contains a function that does not |
|
| support suspend/resume. |
|
| Once the function is in suspend, it shall signal the host by clearing the BS and BR |
|
| bits. The host can monitor the status of the suspend request by reading the BR bit. If |
|
| it is set, the suspend request is still in progress. A pending suspend request can be |
|
| cancelled by the host by writing 0 to the BR bit. |
|
| The Standard Host Specification defines following suspend sequence: |
|
| If the suspend request is not accepted, the host retries with a cancel suspend request |
|
| command. Even if the card received a cancel suspend command, it should accept |
|
| suspend if possible. If the card does not accept suspend, the host considers the |
|
| function to have never suspend. |
|
| However, the host should monitor the BR, BS and EXx bits to confirm that the |
|
| suspend request was cancelled rather that granted. If SBS=0, this bit shall be R/O |
|
| and read as 0. |
32
