479
/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
and CSD, on the receiving side, these two register reserved bits [0] are replaced with the end bit of the response. The
actual erase operation may take a long time, and the host can send a CMD7 command to deselect the card.
Table 18-26 R2 response
Bit
Width
Value
Description
135
1
0
Start bit
134
1
0
Transmission bit
[133:128]
6
‘111111’
Command index
[127:1]
127
X
Card status
0
1
1
End bit
R3 (OCR register)
The R3 code length is 48 bits. The response of CMD1 is saved in the OCR register and sent. The definition of the
level code is: the limited voltage window is low and the card is busy.
Table 18-27 R3 response
Bit
Width
Value
Description
47
1
0
Start bit
46
1
0
Transmission bit
[45:40]
6
‘111111’
Reserved
[39:8]
32
X
OCR register
[7:1]
7
‘1111111’
Reserved
0
1
1
End bit
R4 (Fast I/O)
The R4 code is 48 bits long and is only applicable to MMC cards. The parameter field includes the RCA of the
specified card, the address of the register that needs to be read or written, and its content.
Table 18-28 R4 response
Bit
Width
Value
Description
47
1
0
Start bit
46
1
0
Transmission bit
[45:40]
6
‘111111’
Reserved
[39:8]Argument
field
[31:16]
16
x
RCA
[15:8]
8
x
Register address
[7:0]
8
x
Read register contents
[7:1]
7
‘1111111’
CRC7
0
1
End bit
R4b
R4b is only available for SD I/O cards, and the code length is 48 bits. The SDIO card will return a unique SDIO
response R4 after receiving the CMD5 command.