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Data link layer, Data link layer -4 – Altera Arria 10 Avalon-MM DMA User Manual

Page 116

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• The Gen1, Gen2, and Gen3 simulation models support PIPE and serial simulation.

• For Gen3, the Altera BFM bypasses Gen3 Phase 2 and Phase 3 Equalization. However, Gen3 variants

can perform Phase 2 and Phase 3 equalization if instructed by a third-party BFM.

Related Information

PIPE Interface Signals

on page 5-22

Data Link Layer

The Data Link Layer is located between the Transaction Layer and the Physical Layer. It maintains packet

integrity and communicates (by DLL packet transmission) at the PCI Express link level (as opposed to

component communication by TLP transmission in the interconnect fabric).
The DLL implements the following functions:
• Link management through the reception and transmission of DLL packets (DLLP), which are used for

the following functions:
• Power management of DLLP reception and transmission

• To transmit and receive

ACK

/

NACK

packets

• Data integrity through generation and checking of CRCs for TLPs and DLLPs

• TLP retransmission in case of

NAK

DLLP reception using the retry buffer

• Management of the retry buffer

• Link retraining requests in case of error through the Link Training and Status State Machine

(LTSSM) of the Physical Layer

9-4

Data Link Layer

UG-01145_avmm_dma

2015.05.14

Altera Corporation

IP Core Architecture

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