Sd Bus Topology - SanDisk SDSDB-016G-A11 Product Manual

Revision 2.2
3.2

SD Bus Topology

The SD Memory Card bus has six communication lines and three supply lines.
CMD
DAT0-3
CLK
VDD
VSS[1:2]
The description of each signal is contained in Table 3-3.
Table 3-3
Name
CMD
DAT0-3
CLK
V
DD
V [1:2]
SS
Figure 3-2 shows the bus topology of several cards with one host in SD Bus mode.
Figure 3-2
© 2004 SanDisk Corporation
MMC Bus Signal Descriptions
Command is a bi-directional signal. Host and card drivers are operating in push-
pull mode.
Data lines are bi-directional signals. Host and card drivers are operating in push-
pull mode.
Clock is a host to card signal. CLK operates in push-pull mode.
Power supply line for all cards.
Two ground lines.
SD Card System Bus Topology
HOST
CLK
Vdd
Vss
D0-3(A),
CMD(A)
D0-3(B),
CMD(B)
D0-3(C)
CMD(C)
3-3
Chapter 3 – SD Card Interface Description
SD Card Product Manual
Description
CLK
Vdd
Vss SD Memory
Card (A)
D0-D3, CMD
CLK
Vdd
Vss SD Memory
Card (B)
D0-D3, CMD
CLK
Vdd
Vss MultiMediaCard
(C)
D0, CS, CMD
D1&D2 Not
Connected
12/08/04