SD Card Interface Description
SanDisk Secure Digital (SD) Card Product Manual, Rev. 1.9 © 2003 SANDISK CORPORATION
3-3
Figure 3-1. SD Card Architecture
3.2. SD Bus Topology
The SD bus has six communication lines and three supply lines:
•
CMD
—Command is a bi-directional signal. (Host and card drivers are operating in push pull mode.)
•
DAT0-3
—Data lines are bi-directional signals. (Host and card drivers are operating in push pull
mode.)
•
CLK
—Clock is a host to cards signal. (CLK operates in push pull mode.)
•
VDD
—VDD is the power supply line for all cards.
•
VSS[1:2]
—VSS are two ground lines.