Product manual

Industrial Grade SD Card Interface Description
3-8 SanDisk Industrial Grade SD Product Manual, Rev. 1.0 © 2003 SANDISK CORPORATION
Every bus master shall have the capability to implement ACMD41 and CMD1. CMD1 will be used to ask
MultiMediaCards to send their Operation Conditions. In any case the ACMD41 or the CMD1 shall be send
separately to each card accessing it through its own CMD line.
3.4.2. Bus Operating Conditions
SPI Mode bus operating conditions are identical to SD Card mode bus operating conditions. Table 3-4 lists the
power supply voltages. The CS (chip select) signal timing is identical to the input signal timing (see Figure 3-7).
Table 3-4. Power Supply Voltage
General
Parameter Symbol Min. Max. Unit Remark
Peak voltage on all lines -0.3 VDD+0.3 V
All Inputs
Input Leakage Current -10 10
µA
All Outputs
Output Leakage Current -10 10
µA
Power Supply Voltage
Parameter Symbol Min. Max. Unit Remark
Supply Voltage V
DD
2.0 3.6 V CMD0, 15, 55,
ACMD41 commands
Supply Voltage 2.7 3.6 V Except CMD0, 15, 55,
ACMD41 commands
Supply voltage differentials (V
SS1
, V
SS2
) -0.3 0.3 V
Power up Time 250 mS From 0V to V
DD
Min.
3.4.3. Bus Signal Line Load
The total capacitance CL of the CLK line of the SD Card bus is the sum of the bus master capacitance CHOST, the
bus capacitance CBUS itself and the capacitance CCARD of each card connected to this line:
CL = CHOST + CBUS + N∗CCARD
Where N is the number of connected cards. Requiring the sum of the host and bus capacitances not to exceed 30 pF
for up to 10 cards, and 40 pF for up to 30 cards, the values in Table 3-5must not be exceeded.
Table 3-5. Signal Line’s Load
Parameter Symbol Min. Max. Unit Remark
Pull-up resistance R
CMD
R
DAT
10 100
kΩ
To prevent bus floating
Bus signal line capacitance C
L
250 pF f
PP
≤ 5 MHz, 21 cards
Bus signal line capacitance C
L
100 pF f
PP
≤ 20 MHz, 7 cards
Single card capacitance C
CARD
10 pF