Command Classes; Detailed Command Description - SanDisk SDSDB-32-201-80 - Industrial Grade Flash Memory Card Product Manual

Commands and arguments are listed in Table 5-2.
7-bit CRC Calculation: G(x) = x
39
M(x) = (start bit) x + (host bit) x
CRC[6...0] = Remainder[(M(x) x

5.2.2. Command Classes

As in SD mode, the SPI commands are divided into several classes (See Table 5-1). Each class supports a set of
card functions. An SD Card will support the same set of optional command classes in both communication modes
(there is only one command class table in the CSD register). The available command classes, and the supported
commands for a specific class, however, are different in the SD Card and the SPI communication mode.
Note that except the classes that are not supported in SPI mode (class 1, 3 and 9), the mandatory required classes for
the SD mode are the same for the SPI mode.
Card CMD Class Class Description
(CCC)
class 0 Basic
class 1 Not supported in SPI
class 2 Block read
class 3 Not supported in SPI
class 4 Block write
class 5 Erase
class 6 Write-protection (Optional)
class 7 Lock Card (Optional)*
class 8 Application specific
class 9 Not supported in SPI
class 10-11 Reserved
* The Lock Card command is supported in the SD Card.

5.2.2.1. Detailed Command Description

The following table provides a detailed description of the SPI bus commands. The responses are defined in Section
5.2.3. Table 5-2 lists all SD Card commands. A "yes" in the SPI mode column indicates that the command is
supported in SPI mode. With these restrictions, the command class description in the CSD is still valid. If a
command does not require an argument, the value of this field should be set to zero. The reserved commands are
reserved in SD Card mode as well.
The binary code of a command is defined by the mnemonic symbol. As an example, the content of the Command
field for CMD0 is (binary) '000000' and for CMD39 is (binary) '100111.'
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
7 + 3 +
x 1
38
+...+ (last bit before CRC) x
7
)/G(x)]
Table 5-1. Command Classes in SPI Mode
0 1 9 10 12 13 16 17 18 24 25 27 28 29 30 32 33 38 42 55 56 58 59
+ + + + + +
0
Supported Commands
+ + +
+ + +
+ + +
SPI Protocol Definition
+ +
+ + +
+
+ +
5-9