Intel PXA27 Series Design Manual page 289

Glossary
SOP. Start-of-Packet
SPI. See System Programming Interface. Also, see Serial Peripheral Interface protocol.
SPI. Serial Peripheral Interface
Split transaction. A transaction type supported by host controllers and hubs. This transaction type allows full- and
low-speed devices to be attached to hubs operating at high-speed.
Spread Spectrum. An encoding technique patented by actress Hedy Lamarr and composer George Antheil, which
broadcasts a signal over a range of frequencies.
SRAM. Static Random Access Memory
SRC. See Sample Rate Conversion.
SSE. Streaming SIMD Extensions
SSE2. Streaming SIMD Extensions 2: for Intel Architecture machines, 144 new instructions, a 128-bit SIMD
integer arithmetic and 128-bit SIMD double precision floating point instructions, enabling enhanced multimedia
experiences.
SRP. Session Request Protocol
SSP. Synchronous Serial Port
SSTL. Stub Series Terminated Logic
Stage. One part of the sequence composing a control transfer; stages include the Setup stage, the Data stage, and the
Status stage.
Start-of-Frame (SOF). The first transaction in each (micro)frame. An SOF allows endpoints to identify the start of
the (micro)frame and synchronize internal endpoint clocks to the host.
STN. Supertwist Nematic. A passive LCD display using the technique of twisting light rays to improve the quality
of the LCD screens. Passive LCD displays apply either full-on voltage or full-off voltage (on or off) during each
frame refresh. By intelligently turning the pixel on and off each frame a partial intensity is affected on each pixel.
This process is known as "dithering."
Stream Pipe. A pipe that transfers data as a stream of samples with no defined USB structure
SWI. Software Interrupt
Synchronization Type. A classification that characterizes an isochronous endpoint's capability to connect to other
isochronous endpoints.
Synchronous RA. The incoming data rate, Fsi, and the outgoing data rate, Fso, of the RA process are derived from
the same master clock. There is a fixed relation between Fsi and Fso.
Synchronous SRC. The incoming sample rate, Fsi, and outgoing sample rate, Fso, of the SRC process are derived
from the same master clock. There is a fixed relation between Fsi and Fso.
System Programming Interface (SPI). A defined interface to services provided by system software.
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Intel PXA27x Processor Family Design Guide Glossary-13