MultiMediaCardTM
SPEC_VERS
Defines the Spec version supported by the card. It includes the commands set definition and the
definition of the card responses. The card identification procedure is compatible for all spec versions.
SPEC_VERS
System specification version number
“0011”
System specification version 3.31
The Spec version of these Samsung MultiMediaCards is related to the “MultiMediaCard system
specification,Version 3.31”. The parameter SPEC_VERS has permanently the value “0011”.
TAAC
Defines the asynchronous data access time:
TAAC bit
Description
Values
2:0
Time exponent
0 = 1 ns, 1 = 10 ns, 2 = 100 ns, 3 = 1
ms, 4 = 10 ms, 5= 100 ms, 6 = 1 ms,
7 = 10 ms
6:3
Time mantissa
0 = reserved, 1 = 1.0, 2 = 1.2, 3 = 1.3,
5 = 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
Always ‘0’
7
Reserved
The value for the asynchronous delay for these MultiMediaCards is 1.5 ms. The coded TAAC value is
0x26 (= 1.5 ms).
NSAC
Defines the worst case for synchronous data access time. The unit for NSAC is 100-clock cycles.
Therefore, maximum value for the data access time is 25.6K clock cycles. The total access time NAC as
expressed in the Table “Timing Values” is the sum of both TAAC and NSAC. It has to be computed by
the host for actual clock rate. The read access time should be interpreted as a typical delay for the first
data bit of a data block or stream. The value of NSAC for these MultiMediaCards is 0x01 (100-clock
cycles). For more details refer to Chapter “Operating Characteristics”.
TRAN_SPEED
The following table defines the maximum data transfer rate TRAN_SPEED:
Maximum Data Transfer Rate Definition
TRAN_SPEED bit
Description
Values
2:0
Transfer rate exponent
0 = 100 kbit/s, 1 = 1 Mbit/s, 2 = 10
Mbit/s, 3 = 100 Mbit/s, 4...7 =
reserved
6:3
Time mantissa
0x0 = reserved, 0x1 = 1.0, 0x2 = 1.2,
0x3 = 1.3, 0x4 = 1.5, 0x5 = 2.0, 0x6 =
2.5, 0x7 = 3.0, 0x8 = 3.5, 0x9 = 4.0,
0xA = 4.5, 0xB = 5.0, 0xC = 5.5, 0xD
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