SanDisk SDSDB-016G-A11 - Command Classes; Command Format

Chapter 4 – SD Card Protocol Description
Revision 2.2 SanDisk SD Card Product Manual
© 2004 SanDisk Corporation 4-31 12/08/04
4.8.2 Command Format
The command length shown in Figure 4-15 is 48 bits.
Figure 4-15 Format (1.92 µs @ 25 MHz)
0 1 bit 5….bit 0 bit 31….bit 0 bit 6….bit 0 1
start bit host command argument CRC7 end bit
Commands and arguments are listed in Table 4-13.
7-bit CRC Calculation: G(x) = x
7+
x
3+
1
M(x) = (start bit)*x
39
+ (host bit)*x
38
+…+ (last bit before CRC)*x
0
CRC[6…0] = Remainder[(M(x)*x
7
)/G(x)]
4.8.3 Command Classes
The command set of the SD Card is divided into several classes (refer to Table 4-15). Each
class supports a set of card functions.
The supported Card Command Classes (CCC) is coded as a parameter in the CSD Register
data of each card, providing the host with information on how to access the card.
Table 4-15 Card Command Classes
Class 0 1 2 3 4 5 6 7 8 9 10 11
CMD
Basic R Block
Read
R Block
Write
Erase Write
Protec
tion
Lock
Card
App-
Specific
I/O
Mode
Switch R
CMD0 +
CMD2 +
CMD3 +
CMD4 +
CMD5 +
CMD6
20
+
CMD7 +
CMD9 +
CMD10 +
CMD12 +
CMD13 +
CMD15 +
CMD16 + + +
CMD17 +
CMD18 +
CMD24 +
CMD25 +
CMD27 +
20
This command is newly defined in SD Card Physical Description Spec. v1.10