Specifications

©Copyright 2001-2013 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 4.10
107
4.13.3.3 Speed Grade Measurement Conditions
Speed Grades Measurement Conditions are defined in Table 4-60.
Item
Definition
Pw Measurement
Conditions for UHS-I
Performance is measured the same as Pw under following conditions.
SDCLK=80MHz for SDR and 40MHz for DDR
RU=512KB, Power Limit=1.44W (400mA at 3.6V)
An AU Size is used described in UHS_AU_SIZE (Up to 64MB).
The measurement method of UHS-
I performance is the same as SDXC.
If
AU size is larger than 4MB, performance is measured in each 4MB
sub-unit.
Pw Measurement
Conditions for UHS-II
Performance is measured the same as Pw under following conditions.
RU=512KB, Power Limit=1.44W (400mA at 3.6V)
An AU Size is used described in UHS_AU_SIZE (Up to 64MB).
RCLK=35MHz, Transmission Speed Range=Range A (x15 Multiplier)
In FD Mode and Fast Mode. N_FCU=1.
The measurement method of UHS-I
I performance is the same as
SDXC. Performance is measured in each 4MB sub-unit.
FAT Update / CI Update
Same as existing Speed Class
Write busy
Each write busy shall be less than or equal to 250ms
Except DIR write of SDXC card may be up to 500ms
Table 4-60 : Speed Grade Measurement Conditions for UHS-I and UHS-II
4.13.3.4 Notes for Preparation Time of UHS-I and UHS-II Card
At the beginning of a recording, the SD Memory Card indicates busy as preparation time to start Speed
Class Recording. The maximum preparation time is considered as 1 second. If CMD20 is received, the
card shall indicate the preparation time in busy of CMD20 Start Recording. If CMD20 is not received,
the card should indicate the preparation time in the busy of write operations, which writes to the first AU.
In this case, the card is not necessary to include preparation time of the first AU in Pw and host should
estimate 1 second preparation time to write the first AU.
4.13.3.5 Host Operating Frequency
In case of Non UHS-II mode, Host needs to use higher frequency clock than that of measurement
condition.
In case of UHS-II mode, as Speed Grade of card is measured at 35MHz Range A, host needs to set
higher bit rate than measurement bit rate to use Speed Grade. That is when UHS-II is used in
Transmission Speed Range A (x15 Multiplier), host needs to provide RCLK more than or equal to
35MHz. When UHS-II card is used in Transmission Speed Range B (x30 Multiplier), any frequency of
RCLK range (26MHz - 52MHz) may be used.