SDI Technologies SDIO Card Manual Do Utilizador

SDIO Simplified Specification Version 2.00

3.3

The 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

Number

of I/O

functions

Memory

Present

Stuff

Bits

I/O OCR

Reserved E

1 1

Figure 3-5 Response R4 in SD mode

Modified

Number

of I/O

functions

Memory

Present

Stuff Bits

I/O OCR

8 1 3

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.

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:

Figure 3-7 Modified R1 Response

Stuff Bits:

Not used, shall be set to 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)