Altera Arria 10 Avalon-ST User Manual

Page 262

Advertising
background image

Possible Causes

Symptoms and Root Causes

Workarounds and Solutions

Malformed TLP is

transmitted

Refer to the error log file to find

the last good packet transmitted

on the link. Correlate this packet

with TLP sent on Avalon-ST

interface. Determine if the last

TLP sent has any of the

following errors:
• The actual payload sent does

not match the length field.

• The format and type fields

are incorrectly specified.

• TD field is asserted,

indicating the presence of a

TLP digest (ECRC), but the

ECRC dword is not present

at the end of TLP.

• The payload crosses a 4KByte

boundary.

Revise the Application Layer logic to correct the

error condition.

Insufficient Posted

credits released by

Root Port

If a Memory Write TLP is

transmitted with a payload

greater than the maximum

payload size, the Root Port may

release an incorrect posted data

credit to the Endpoint in

simulation. As a result, the

Endpoint does not have enough

credits to send additional

Memory Write Requests.

Make sure Application Layer sends Memory

Write Requests with a payload less than or equal

the value specified by the maximum payload

size.

Missing completion

packets or dropped

packets

The RX Completion TLP might

cause the RX FIFO to overflow.

Make sure that the total

outstanding read data of all

pending Memory Read Requests

is smaller than the allocated

completion credits in RX buffer.

You must ensure that the data for all

outstanding read requests does not exceed the

completion credits in the RX buffer.

Related Information

PIPE Interface Signals

on page 6-57

Avalon Interface Specifications

PCI Express Base Specification 3.0

Design Debugging Using the SignalTap II Embedded Logic Analyzer

18-4

Debugging Link Failure in L0 Due To Deassertion of tx_st_ready

UG-01145_avst

2015.05.04

Altera Corporation

Debugging

Send Feedback

Advertising