©Copyright 2000-2007 SD Card Association

SDIO Simplified Specification Version 2.00

3.3The IO_SEND_OP_COND Response (R4)

An SDIO card receiving CMD5 shall respond with a SDIO unique response, R4. The format of R4 for both the SD and SPI modes is:

S

D

Reserved

C

Number Memory

of I/O Present functions

Stuff

Bits

I/O OCR

Reserved

E

1

1

6

1

3

1

3

24

7

1

Figure 3-5 Response R4 in SD mode

Modified

R1

C

Number Memory

of I/O Present functions

Stuff Bits

I/O OCR

8

1

3

1

3

24

Figure 3-6 Response R4 in SPI mode

The Response, R4 contains the following data:

S(tart bit):

 

 

 

Start bit. Always 0

 

 

 

 

 

D(irection):

 

 

 

Direction. Always 0. Indicates transfer from card to host.

Reserved:

 

 

 

Bits reserved for future use. These bits shall be set to 1.

C:

 

 

 

Set to 1 if Card is ready to operate after initialization

I/O OCR:

 

 

 

Operation Conditions Register. The supported minimum and maximum values

 

 

 

 

for VDD. The layout of the OCR is shown in Table 3-1. See section 4.10.1 for

 

 

 

 

additional information.

Memory Present:

 

 

 

Set to 1 if the card also contains SD memory. Set to 0 if the card is I/O only.

Number of I/O Functions:

Indicates the total number of I/O functions supported by this card. The range is 0-7.

 

 

 

 

Note that the common area present on all I/O cards at Function 0 is not included in

 

 

 

 

this count. The I/O functions shall be implemented sequentially beginning at

 

 

 

 

function 1.

 

 

 

 

 

Modified R1:

 

 

 

The SPI R1 response byte as described in the SD Physical Specification modified

 

 

 

 

for I/O as follows:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

0

 

 

 

 

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 = in idle state

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RFU (always 0)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 = illegal command

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 = COM CRC error

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 = Function number error

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RFU (always 0)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 = parameter error

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Start Bit (always 0)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 3-7 Modified R1 Response

Stuff Bits:

Not used, shall be set to 0.

 

 

 

 

 

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SDI Technologies SDIO Card manual Iosendopcond Response R4, Response R4 in SD mode