SanDisk SDSDB-32-201-80 - Industrial Grade Flash Memory Card Product Manual page 40

NOTE: The device size indicates the user area size. It does not include the protected area that is used for security applications
and is about 1 percent of the total card size.
The following sections describe the CSD fields and the relevant data types. If not explicitly defined otherwise, all
bit strings are interpreted as binary coded numbers starting with the left bit first.
CSD_STRUCTURE—describes the version of the CSD structure.
CSD_STRUCTURE
TAAC—Defines the asynchronous part (relative to the SD Card clock (CLK)) of the read access time.
TAAC Bit
Position
2:0
6:3
7
NSAC—Defines the worst case for the clock dependent factor of the data access time. The unit for NSAC is 100
clock cycles. Therefore, the maximal value for the clock dependent part of the read access time is 25.5k clock
cycles.
The total read access time N
by the host for the actual clock rate. The read access time should be interpreted as a typical delay for the first data
bit of a data block from the end bit on the read commands.
TRAN_SPEED—Table 3-13 defines the maximum data transfer rate TRAN_SPEED.
TRAN_SPEED Bit
CCC—The SD Card command set is divided into subsets (command classes). The card command class register
CCC defines which command classes are supported by this card. A value of '1' in a CCC bit means that the
corresponding command class is supported. Table 3-14 lists the supported card command classes; refer to Table 4-2
for command class definitions.
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
Table 3-11. CSD Register Structure
CSD Structure Version
0 CSD version No. 1.0
1-3 Reserved
Table 3-12. TAAC Access Time Definition
time unit
0=1ns, 1=10ns, 2=100ns, 3=1µms, 4=10µms, 5=100µms, 6=1ms, 7=10ms
time value
0=reserved, 1=1.0, 2=1.2, 3=1.3, 4=1.5, 5=2.0, 6=2.5, 7=3.0, 8=3.5, 9=4.0,
A=4.5, B=5.0, C=5.5, D=6.0, E=7.0, F=8.0
Reserved
as expressed in the Table 5-17 is the sum of TAAC and NSAC. It has to be computed
AC
Table 3-13. Maximum Data Transfer Rate Definition
2:0 transfer rate unit
0=100kbit/s, 1=1Mbit/s, 2=10Mbit/s, 3=100Mbit/s, 4... 7=reserved
6:3 time value
0=reserved, 1=1.0, 2=1.2, 3=1.3, 4=1.5, 5=2.0, 6=2.5, 7=3.0,
8=3.5, 9=4.0, A=4.5, B=5.0, C=5.5, D=6.0, E=7.0, F=8.0
7 Reserved
Valid for SD Card Physical
Specification Version
Version 1.0-1.01
Code
Code
SD Card Interface Description
3-15