Table of Contents
Advertisement
MultiMediaCard Product Manual
Bus Signal Line Load
The total capacitance CL of each line of the MultiMediaCard 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 following values must not be exceeded:
Parameter
Pull-up resistance
Bus signal line capacitance
Bus signal line capacitance
Single card capacitance
Maximum signal line inductance
4.4.3
Bus Signal Levels
As the bus can be supplied with a variable supply voltage, all signal levels are related to the supply
voltage.
Input
High
Level
Input
Low
Level
24
Symbol
RCMD
RDAT
CL
CL
CCARD
V
V
DD
V
OH
V
IH
Figure 4-4 Bus Signal Levels
SanDisk MultiMediaCard Product Manual Rev. 2 © 2000 SANDISK CORPORATION
M i n .
M a x .
Unit
50
100
k
250
pF
100
pF
7
pF
16
nH
Undefined
V
IL
V
OL
V
SS
t
Remark
To prevent bus floating
fPP 5 MHz,
30 cards
fPP 20 MHz,
10 cards
fPP 20 MHz
Output
High
Level
Output
Low
Level
Advertisement
Table of Contents
