Datasheet
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APPLICATION INFORMATION
EXTENDING THE MEMORY STICK INTERFACE USING LVDS SIGNALING OVER DIFFERENTIAL
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
SN65LVDT41
SLLS530B – APRIL 2002 – REVISED FEBRUARY 2006
TRANSMISSION CABLES
Figure 14. System Level Block Diagram
The Memory Stick signaling interface operates in a LVDS, as specified by the TIA/EIA-644-A standard,
master-slave architecture, with three active signal provides several benefits when compared to
lines. The host (master) supplies a clock (SCLK) and alternative long-distance signaling technologies: low
bus-state (BS) signal to control the operation of the radiated emissions, high noise immunity, low power
system. The SCLK and BS signals are unidirectional consumption, inexpensive interconnect cables.
(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
and receivers specifically targeted at implementing a
bidirectional (half-duplex) signal used to communicate
Memory Stick interconnect extension. It utilizes
both control and data information between the host
simplex links for the SCLK and BS signals, and two
and the 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 is also carried
The basic Memory Stick interface is capable of from the host to the Memory Stick on a simplex LVDS
operating only over short distances due to the link.
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 14 . A suggested CBT device for this
applications where a greater distance is needed
application is the SN74CBTLV1G125 from Texas
between the host controller and the Memory Stick, it
Instruments Incorporated. These devices are
is necessary to utilize a different signaling method
available in space saving SOT-23 or SC-70
such as low voltage differential signaling, or LVDS.
packages.
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