Chapter 4 – SD Card Protocol Description
Revision 2.2
SanDisk SD Card Product Manual
© 2004 SanDisk Corporation
4-40
12/08/04
Current
Status
idle
ready
ident
stby
tran
data
rcv
prg
dis
ina
State Change
Trigger
Changes to
Class 10
CMD6
-
- - - data
-
- - - -
CMD34-37, 50,
57
-
- - - tran
-
- - - -
Class 11
CMD41,
CMD43…CMD
49, CMD58-59
Reserved
CMD60…
CMD63
Reserved for manufacturer
4.9.1 Responses
All responses are sent on the CMD line. The response transmission always starts with the
MSB. The response length depends on the response type.
A response always starts with a start bit (0), followed by the bit indicating the direction of
transmission (card = 0). A value denoted by
x
in the Table 4-19 to 4-22 indicates a variable
entry. All responses except for the type R3 are protected by a CRC. The end bit (1)
terminates every response.
There are five types of responses supported in the SanDisk SD Card. Their formats are
defined as follows:
1)
R1
(standard response): response length 48 bit.
Bits 45:40 indicate the index of the command to which it is responding. The status of the
card is coded in 32 bits.
Table 4-19
Response R1
Bit Position
47
46
[45:40]
[39:8] [7:1] 0
Width (bits)
1 1
6
32
7
1
Value
0 0
x
x
x
1
Description
start bit
transmission bit
command index
card status
CRC7
end bit