Altera Stratix GX Transceiver - Manual (Page 132)

5–20 Altera Corporation
Stratix GX Transceiver User Guide January 2005
XAUI Mode Transmitter Architecture
XGMII Character to PCS Code-Group Mapping
In XAUI mode, the 8b/10b encoder in the Stratix GX transceiver is
controlled by a global transmitter state machine that maps various 8-bit
XGMII codes to 10-bit PCS code-groups. This state machine complies
with the IEEE 802.3ae PCS transmit specification. For reference, the PCS
transmit source state diagram, specified in clause 48 of the IEEE P802.3ae
specification, is shown in
Figure 5–17 .
Figure 5–17. IEEE 802.3ae PCS Transmit Source State Diagram
SEND_RANDOM_R
tx_code-group<39:0> ||R||
PUDR
SEND_DATA
IF TX=||T|| THEN cvtx_terminate
tx_code-group<39:0>
ENCODE(TX)
PUDR
!reset *
!(TX=||IDLE|| + TX=||Q||)
SEND_A
tx_code-group<39:0> ||A||
next_ifg K
PUDR
SEND_Q
tx_code-group(39:0> TQMSG
Q_det false
PUDR
SEND_RANDOM_A
tx_code-group<39:0> ||A||
PUDR
SEND_RANDOM_K
tx_code-group<39:0> ||K||
PUDR
SEND_K
tx_code-group<39:0> ||K||
next_ifg A
PUDR
next_ifg=A * A_CNT=0
(next_ifg=K + A_CNT 0)
reset
UCT
A_CNT 0 *
code_sel=1
A_CNT 0 *
code_sel=0
A_CNT=0
Q_det !Q_det
UCT
A_CNT 0 *
code_sel=0
A_CNT 0 *
code_sel=1
A_CNT=0
Q_det
!Q_det *
code_sel=1
!Q_det *
code_sel=0
code_sel=0
code_sel=1
SEND_RANDOM_Q
tx_code-group<39:0> TQMSG
Q_det false
PUDR