Datasheet
www.ti.com
APPLICATION INFORMATION
1Y
1Z
1D
1A
1B
5Y
5Z
1R
5D
2Y
2Z
2D
2A
2B
2R
3Y
3Z
3D
3A
3B
3R
4Y
4Z
4D
4A
4B
4R
5A
5B
5R
SCLK
BS
DIR
SD1
SD2
CBT
SCLK
BS
SDIO
Memory
Stick
CBT
SCLK
BS
SDIO
DIR
Memory
Stick
Host
Controller
SN65LVDT41 SN65LVDT14
SN65LVDT14-EP, SN65LVDT41-EP
SCES633 – JUNE 2005
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Extending the Memory Stick Interface Using LVDS Signaling
Over Differential Transmission Cables
Figure 14. System-Level Block Diagram
LVDS, as specified by the TIA/EIA-644-A standard,
The Memory Stick signaling interface operates in a
provides several benefits when compared to
master-slave architecture, with three active signal
alternative long-distance signaling technologies: low
lines. The host (master) supplies a clock (SCLK) and
radiated emissions, high noise immunity, low power
bus-state (BS) signal to control the operation of the
consumption, and inexpensive interconnect cables.
system. The SCLK and BS signals are unidirectional
(simplex) from the host to the Memory Stick. The This device pair provides the necessary LVDS drivers
serial data input/output (SDIO) signal is a bidirectional and receivers specifically targeted at implementing a
(half-duplex) signal used to communicate both control Memory Stick interconnect extension. It utilizes
and data information between the host and the simplex links for the SCLK and BS signals and two
Memory Stick. The direction of data control is simplex links for the SDIO data. The half-duplex
managed by the host through a combination of BS SDIO data is split into two simplex streams under
line states and control information delivered to the control of the host processor by means of the
Memory Stick. direction (DIR) signal. The DIR signal also is carried
from the host to the Memory Stick on a simplex LVDS
The basic Memory Stick interface is capable of
link.
operating only over short distances due to the
single-ended nature of the digital I/O signals. Such a The switching of the SDIO signal-flow direction in the
configuration is entirely suitable for compact and single-ended interfaces is managed by electronic
portable devices where there is little if any separation switch devices, identified by the CBT symbol in
between the host and the Memory Stick. In Figure 7 . A suggested CBT device for this application
applications where a greater distance is needed is the TI SN74CBTLV1G125. These devices are
between the host controller and the Memory Stick, it available in space-saving SOT-23 or SC-70
is necessary to utilize a different signaling method, packages.
such as low-voltage differential signaling, or LVDS.
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