User guide

Altera Corporation 5–3
January 2005 Stratix GX Transceiver User Guide
XAUI Mode
XAUI functions as a self-managed interface because code-group
synchronization, channel deskew, and clock domain decoupling are
handled with no upper layer support requirements. These features are
accomplished based on Physical Coding Sublayer (PCS) code-groups that
are used during the Inter-Packet Gap (IPG) time and during idle periods.
PCS code-groups are mapped by the XGMII Extender Sublayer (XGXS) to
XGMII characters, as specified in Table 5–1.
Figure 5–2 shows an example of the mapping between XGMII characters
to the PCS code-groups used in XAUI. The idle characters are mapped to
a pseudorandom sequence of ||A||, ||R||, and ||K|| code-groups.
Table 5–1. XGMII Character to PCS Code-Group Mapping Note (1)
XGMII TXC XGMII TXD PCD Code-Group Description
0 00 through FF Dxx,y Normal data
transmission
1 07 K28.0 or K28.3 or
K28.5
Idle in ||I||
1 07 K28.5 Idle in ||T||
1 9C K28.4 Sequence
1 FB K27.7 Start
1 FD K29.7 Terminate
1 FE K30.7 Error
1 Reserved XGMII
character
1 Any other value K30.7 Invalid XGMII
character
Note to Ta b le 5 –1 :
(1) Values in TXD column are in hexadecimal.