Altera Stratix GX Transceiver - Manual (Page 156)

6–2 Altera Corporation
Stratix GX Transceiver User Guide January 2005
Introduction
Figure 6–1. GMII Position Relative to OSI Reference Model
Stratix GX devices are used for the PCS and the PMA layers of the GigE
physical layer. Stratix GX devices in GigE mode use built-in hard macros
for the 8B/10B encoder/decoder, rate matcher, synchronizer, or the byte
serializer/deserializer.
Figure 6–2 shows these components. The rate
matcher and the word aligner contain a dedicated state machine
governing their functions, which is active only in GigE mode. GigE mode
enables transceivers to support GMII-to-PCS code group conversion and
idle generation.
Table 6–1 shows the GigE code groups for the reference
of idle ordered sets and configuration ordered sets, as explained in the
“Idle Generation” section. For full details on the GigE standard and code-
group functionality, refer to clause 36 in the Gigabit Ethernet standard
(IEEE 802.3).
The remaining functions of the PCS—auto negotiation, collision detect,
and carrier detect—must be implemented in user logic or external circuits
if these functions are needed.
Application
Presentation
Session
Transport
Network
Data Link
Physical
OSI Reference
Model Layers
LLC - Logical Link Control
MAC Control (Optional)
MAC - Media Access Control
Reconciliation
PCS
PMA
Medium
PMD
GMII
1000BASE-X
PHY
Higher Layers
LAN
CSMA/CD
Layers
Table 6–1. GigE Code Groups (Part 1 of 2) Note (1)
Code Ordered Set
Number of
Code Groups
Encoding
/C/ Configuration Alternating /C1/ and /C2/ code groups
/C1/ Configuration 1 4 /K28.5/D21.5/Config_Reg (1)