SD Card Interface Description
3-22
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Bits Identifier Type Value
Description
Clear
Cond.
18 Reserved
17 Reserved
16
CID/ CSD_OVERWRITE
E R X
’0’= no error
’1’= error
Can be either one of the following errors:
- The CID register has been already written and
can not be overwritten
- The read only section of the CSD does not
match the card content.
- An attempt to reverse the copy (set as original)
or permanent WP (unprotected) bits was made.
C
15
WP_ERASE_SKIP
S X
’0’= not protected ’1’=
protected
Only partial address space was erased due to
existing write protected blocks.
C
14
CARD_ECC_DISABLE D
S X
’0’= enabled ’1’= disabled The command has been executed without using
the internal ECC.
A
13
ERASE_RESET
S R
’0’= cleared ’1’= set
An erase sequence was cleared before
executing because an out of erase sequence
command was received.
C
12:9 CURRENT_STATE
S X
0 = idle
1 = ready
2 = ident
3 = stby
4 = tran
5 = data
6 = rcv
7 = prg
8 = dis
9-15 = reserved
The state of the card when receiving the
command. If the command execution causes a
state change, it will be visible to the host in the
response to the next command.
The four bits are interpreted as a binary coded
number between 0 and 15.
B
8
READY_FOR_DATA
S X
’0’= not ready
’1’= ready
Corresponds to buffer empty signalling on the
bus.
A
7:6
5
APP_CMD
S R
‘0’ = Disabled
‘1’ = Enabled
The card will expect ACMD, or indication that the
command has been interpreted as ACMD.
C
4 Reserved
3 AKE_SEQ_ERROR
(SD Card Security spec.)
E R
‘0’ = no error
‘1’ = error
Error in the sequence of authentication process.
C
2
Reserved for application specific commands
1, 0
Reserved for manufacturer test mode