Intel® Arria® 10 and Intel® Cyclone® 10 GX Avalon® Streaming Interface for PCI Express* User Guide

ID 683647
Date 6/03/2021
Public
Document Table of Contents

5.8. Parity Signals

Parity protection provides some data protection in systems that do not use ECRC checking. Parity is odd. This option is not available for the Avalon‑MM Intel® Arria® 10 or Intel® Cyclone® 10 GX Hard IP for PCI Express.

On the RX datapath, parity is computed on the incoming TLP prior to the LCRC check in the Data Link Layer. Up to 32 parity bits are propagated to the Application Layer along with the RX Avalon-ST data. The RX datapath also propagates up to 32 parity bits to the Transaction Layer for Configuration TLPs. On the TX datapath, parity generated in the Application Layer is checked in Transaction Layer and the Data Link Layer.

The following table lists the signals that indicate parity errors. When an error is detected, parity error signals are asserted for one cycle.

Table 33.  Parity Signals

Signal Name

Direction

Description

tx_par_err[1:0]

Output

When asserted for a single cycle, indicates a parity error during TX TLP transmission. These errors are logged in the VSEC register. The following encodings are defined:

  • 2’b10: A parity error was detected by the TX Transaction Layer. The TLP is nullified and logged as an uncorrectable internal error in the VSEC registers. For more information, refer to Uncorrectable Internal Error Status Register.
  • 2’b01: Some time later, the parity error is detected by the TX Data Link Layer which drives 2’b01 to indicate the error. Intel recommends resetting the Intel® Arria® 10 or Intel® Cyclone® 10 GX Hard IP for PCI Express when this error is detected. Contact Intel if resetting becomes unworkable.

Note that not all simulation models assert the Transaction Layer error bit in conjunction with the Data Link Layer error bit.

rx_par_err

Output

When asserted for a single cycle, indicates that a parity error was detected in a TLP at the input of the RX buffer. This error is logged as an uncorrectable internal error in the VSEC registers. For more information, refer to Uncorrectable Internal Error Status Register. If this error occurs, you must reset the Hard IP if this error occurs because parity errors can leave the Hard IP in an unknown state.

cfg_par_err

Output

When asserted for a single cycle, indicates that a parity error was detected in a TLP that was routed to internal Configuration Space or to the Configuration Space Shadow Extension Bus. This error is logged as an uncorrectable internal error in the VSEC registers. For more information, refer to Uncorrectable Internal Error Status Register. If this error occurs, you must reset the core because parity errors can put the Hard IP in an unknown state.

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