Specifications

©Copyright 2001-2013 SD Group (Panasonic, SanDisk, Toshiba) and SD Card Association
Physical Layer Simplified Specification Version 4.10
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Appendix B (Normative) : Special Terms
B.1 Terminology
block
A number of bytes, basic data transfer unit
broadcast
A command sent to all cards on the SD bus
Blocklen
Block Length set by CMD16
Distributed
A signal path between host and card which has a distributed system
effects. As described in transmission line theory.
Extension Register
Register defined by a Function Specification in Extension Register
Space.
Extension Register
Space
Register Spaces accessible by CMD48/49/58/59 with 17-bit ADDR
and FNO. There ar
e two types of spaces: memory space and I/O
space.
Flash
A type of multiple time programmable non-volatile memory
Fixed Data Window
There is an overlapped area of valid data window for all delay
variation.
group
A number of sectors, composite erase and write protect unit
Lumped
A signal path between host and card which is considerably small
compared to the signal rise time. It is considered as "lumped" system
open-drain
A logical interface operation mode. An external resistor or current
source is used
to pull the interface level to HIGH, the internal
transistor pushes it to LOW
payload
Net data
push-pull
A logical interface operation mode, a complementary pair of
transistors is used to push the interface level to HIGH or LOW
sector
A number of blocks, basic erase unit
Speed Class
Minimum performance defined in Default and High Speed Modes
Speed Grade
Minimum performance defined in UHS-I and UHS-II mode
stuff bit
Filling bits to ensure fixed length frames for commands and
responses
three-state driver
A driver stage which has three output driver states: HIGH, LOW and
high imped
ance (which means that the interface does not have any
influence on the interface level)
token
Code word representing a command
Tuning
Host adjusts sampling clock by Send Tuning Block Command.
Variable Data Window
An overlapped area of valid data window is not available or too small
for all Process, Voltage and Temperature variations.
B.2 Abbreviations
ACMD6
Set bus width command
ACMD41
Initialization command
AU
Allocation Unit
CID
Card IDentification number register
CLK
clock signal
CMD
command line or SD bus command (if extended CMDXX)
CRC
Cyclic Redundancy Check
CSD
Card Specific Data register
CMD0
Reset command
CMD8
Voltage check command
CMD6
Switch command used for selecting one of UHS-I modes
CMD11
Voltage switch command to change signaling level 3.3V to 1.8V.