Memory Card Specification Sheet

©Copyright 2000-2007 SD Card Association
SDIO Simplified Specification Version 2.00
11
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 C Number
of I/O
functions
Memory
Present
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
of I/O
functions
Memory
Present
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:
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)
00 0