Chapter 3 – SD Card Interface Description
Revision 2.2
SD Card Product Manual
© 2004 SanDisk Corporation
3-11
12/08/04
Parameter Symbol
Min
Max
Unit Remark
Clock (CLK) – all values referred to min. V
IH
and max. V
IL
Output hold time
t
OH
2.5 --- ns
Total system capacitance for
each line
11
C
L
--- 40 pF
3.5
SD Card Registers
There is a set of six registers within the card interface. The OCR, CID, CSD, and SCR
registers carry the card configuration information. The RCA Register holds the card-
relative communication address for the current session. The card status and SD status
registers hold the communication protocol related status of the card.
3.5.1
Operating Conditions Register
The 32-bit
Operation Conditions Register (OCR)
stores the V
DD
voltage profile of the
SanDisk SD Card. The card is capable of executing the voltage recognition procedure
(CMD1) with any standard SD Card host using operating voltages from 2 to 3.6 V.
Accessing the data in the memory array, however, requires 2.7 to 3.6 V. The OCR shows
the voltage range in which the card data can be accessed. The structure of the OCR
Register is described in Table 3-9.
Table 3-9
Operating Conditions Register
OCR Bit
VDD Voltage Window
OCR Bit
VDD Voltage Window
0-3
Reserved
15
2.7 to 2.8
4
1.6 to 1.7
16
2.8 to 2.9
5
1.7 to 1.8
17
2.9 to 3.0
6
1.8 to 1.9
18
3.0 to 3.1
7
1.9 to 2.0
19
3.1 to 3.2
8
2.0 to 2.1
20
3.2 to 3.3
9
2.1 to 2.2
21
3.3 to 3.4
10
2.2 to 2.3
22
3.4 to 3.5
11
2.3 to 2.4
23
3.5 to 3.6
12
2.4 to 2.5
24-30
Reserved
13
2.5 to 2.6
31
Card power-up status bit
14
2.6 to 2.7
11
In order to satisfy severe timing, the host will drive only one card.