R4 (Fast I/O); R4B; Table 126. R3 Response; Table 127. R4 Response - ST STM32F102 Series Reference Manual

SDIO interface (SDIO)

Table 126. R3 response

Bit position
47
46
[45:40]
[39:8]
[7:1]
0
19.5.5

R4 (Fast I/O)

Code length: 48 bits. The argument field contains the RCA of the addressed card, the
register address to be read out or written to, and its content.

Table 127. R4 response

47
46
[45:40]
[39:8] Argument field
[7:1]
0
19.5.6

R4b

For SD I/O only: an SDIO card receiving the CMD5 will respond with a unique SDIO
response R4. The format is:

Table 128. R4b response

47
46
[45:40]
[39:8] Argument field
448/690
Width (bits
1
1
6
32
7
1
Bit position
[31:16]
[15:8]
[7:0]
Bit position
39
[38:36]
35
[34:32]
[31:8]
Value
0
0
'111111'
X
'1111111'
1
Width (bits
1 0
1 0
6 '111111'
16 X
8 X
8 X
7 '1111111'
1 1
Width (bits
1 0
1 0
6 x
16 X
3 X
1 X
3 X
24 X
Description
Start bit
Transmission bit
Reserved
OCR register
Reserved
End bit
Value Description
Start bit
Transmission bit
Reserved
RCA
register address
read register contents
CRC7
End bit
Value Description
Start bit
Transmission bit
Reserved
Card is ready
Number of I/O functions
Present memory
Stuff bits
I/O ORC
RM0008