A. Serial RapidIO Protocol Overview > Physical Layer
484
Tsi578 User Manual
June 6, 2016
Integrated Device Technology
www.idt.com
A.2.1
Control Symbols
Two classes of control symbols are defined (stype0 and stype1) and are used for packet
acknowledgment, link utility functions, link maintenance, and packet delineation. A control symbol is
a 24-bit entity (including a 5-bit CRC code). The control symbol is used for packet delineation by
placement at the beginning of a packet. The control symbol may also be embedded within a packet for
message passing and link status notification as well as sent when the link is idle.
Acknowledgment control symbols are used by processing elements to indicate packet transmission
status. Utility control symbols are used to communicate buffer status and link recovery
synchronization. Link maintenance control symbols are used by link partner devices to communicate
physical layer status, synchronization requests, and device reset.
A.3
Physical Layer
The physical layer is broken into two sub-layers, the PCS and PMA Layers describes the Physical
Coding Sub-layer (PCS) functionality as well as the Physical Media Attachment (PMA) functionality.
A.3.1
PCS Layer
The PCS layer functionality includes 8B/10B encoding scheme for embedding the clock with the data.
It also manages the transmission rules for the 1x and 4x interfaces and defines the link initialization
sequence for clock synchronization. The PCS function is also responsible for idle sequence generation,
encoding for transmission and lane striping, and decoding, lane alignment and de-striping on reception.
The PCS layer also provides methods for determining the operational mode of the port as 4-lane or
1-lane operation, and means to detect link states. It provides for clock difference tolerance between the
sender and receiver without requiring flow control.
A.3.2
PMA Layer
The PMA function is responsible for serializing 10-bit parallel code-groups to/from a serial bit stream
on a lane-by-lane basis. Upon receiving data, the PMA function provides alignment of the received bit
stream to 10-bit code-group boundaries, done independently on a lane-by-lane basis. It then provides a
continuous stream of 10-bit code-groups to the PCS, one stream for each lane. The 10-bit code-groups
are not observable by layers higher than the PCS.
A.3.3
Physical Protocol
The physical connection of a RapidIO link is managed by a series of control symbols transmitted on a
transmit - response basis. These control symbols are made up of 10-bit encoded special characters and
3 byte control symbols. Encoded 8-bit characters are given encoding values and names that allow easy
and unique detection of the character. Detailed explanation of the encoding values and names can be
found in Chapter 4,
“PCS and PMA Layers” of “Part VI Physical Layer 1x/4x LP-Serial RapidIO
Specification”
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Содержание Tsi578
Страница 1: ...IDT Tsi578 Serial RapidIO Switch User Manual June 6 2016 Titl ...
Страница 20: ...About this Document 20 Tsi578 User Manual June 6 2016 Integrated Device Technology www idt com ...
Страница 102: ...4 Internal Switching Fabric Packet Queuing 102 Tsi578 User Manual June 6 2016 Integrated Device Technology www idt com ...
Страница 228: ...11 Signals Pinlist and Ballmap 228 Tsi578 User Manual June 6 2016 Integrated Device Technology www idt com ...
Страница 504: ...B Clocking P_CLK Programming 504 Tsi578 User Manual June 6 2016 Integrated Device Technology www idt com ...
Страница 526: ...Index 526 Tsi578 User Manual June 6 2016 Integrated Device Technology www idt com ...