ORSPI4 datasheet(116/263 Pages) LATTICE

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ORCA ORSPI4 Data Sheet

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This state machine is modeled after draft IEEE 802.3ae, version 2.1 but will also operate properly with version 4.1

implementations. Table 29 and Table 30 describe the state variables used in Figure 56.

Note that it takes four idle ordered sets (ex: k28.5, Dx.y, Dx.y, Dx.y) to bring the state machine from a loss-of-sync

to a sync_acq’d_1 state. Instead, when back-to-back commas are used, it takes a total of ﬁve commas to achieve

the same result as with idle ordered sets.

Table 29. XAUI Link Synchronization State Diagram Notation—Variables

Table 30. XAUI Link Synchronization State Diagram—Functions

Variable

Description

sync_status

FAIL: Lane is not synchronized (correct 10-bit alignment has not been established).

OK: Lane is synchronized.

OK_NOC: Lane is synchronized but a comma character has not been detected in the past 200 code-groups.

enable_CDET

TRUE: Align subsequent 10-bit words to the boundary indicated by the next received comma.

FALSE: Maintain current 10-bit alignment.

gd_cg

Current number of consecutive cg_good indications.

Function

Description

sync_complete

Indication that alignment code-group alignment has been established at the boundary indicated by the

most recently received comma.

cg_comma

Indication that a valid code-group, with correct running disparity, containing a comma has been received.

cg_good

Indication that a valid code-group with the correct running disparity has been received.

cg_bad

Indication that an invalid code-group has been received.

no_comma

Indication that comma timer has expired. The timer is initialized upon receipt of a comma.

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