RapidIO Physical Layer MegaCore Function

Transcription

1 RapidIO Physical Layer MegaCore Function April 2005, MegaCore version Errata Sheet Introduction This document addresses known errata and documentation changes for version of the RapidIO Physical Layer MegaCore Errata are design functional defects or errors. Errata may cause the RapidIO Physical Layer MegaCore function to deviate from published specifications. Documentation changes include typos, errors, unclear descriptions or omissions from current published specifications or product documents. These documentation changes or clarifications will be incorporated into an upcoming release of the RapidIO Physical Layer RapidIO Physical Layer MegaCore Function v2.2.1 Issues Altera has identified the following issues that affect the RapidIO Physical Layer MegaCore function v2.2.1: 1. A Packet ackid Is Sometimes Skipped After a Retried Packet on page The Lane Aligner Sometimes Does Not Align on page The Receiver Sometimes Mistakenly Detects a CRC Error on a Valid Packet on page The End of Packet of a Valid Incoming Packet Is Sometimes Lost on page The Transmitter's Frame Signal Sometimes Toggles Incorrectly, Causing the Receiver to Reject the Packet on page The Transmitter Sometimes Generates an Incorrect CRC When a Packet Larger Than 80 Bytes Is Followed by a Packet with Zero Latency on page A Control Symbol Is Sometimes Overwritten on page An Avoidable Compensation Sequence Insertion Sometimes Causes a Packet to Be Stomped and Retried on page The Header of an Outgoing Packet Is Sometimes Lost on page 6. Altera Corporation 1 ES

2 RapidIO Physical Layer MegaCore Function 10. The Packet Immediately Following a Stomped Packet Sometimes Makes it Through to the Atlantic Interface on page Idle Characters Sometimes Appear in the Start-of-Packet (SOP) Word on the Receiver Signals of the Atlantic Interface on page The CRC of the Previous Packet Sometimes Appears in the SOP Word on the Receiver Signals of the Atlantic Interface on page A Control Symbol Is Sometimes Lost on page A Control Symbol Is Sometimes Retransmitted Endlessly on page 9. A Packet ackid Is Sometimes Skipped After a Retried Packet If the transmitter receives a packet-retry control symbol while the transmit buffer is busy, the ackid status of the next normal packet is incorrectly incremented. This issue affects all variations of the A valid packet is sometimes not accepted. The Lane Aligner Sometimes Does Not Align The lane aligner sometimes gets into a state where it is not aligned and no longer tries to align. This happens when alignment is initiated while alignment is drifting, for example, when the clocks have not entirely stabilized. This issue affects all serial, 4 mode variations of the 2 Altera Corporation

3 RapidIO Physical Layer MegaCore Function v2.2.1 Issues The port_initialized signal remains deasserted, and traffic cannot pass. The MegaCore function must be reset to force re-alignment. If the MegaCore function stays out of alignment for extended periods of time, assert the reset_n signal. The Receiver Sometimes Mistakenly Detects a CRC Error on a Valid Packet When an incoming packet is terminated by the eop/symbol/sop/symbol pattern, the receiver extends the internal end-of-packet data for one more clock cycle, causing the cyclic redundancy code (CRC) checker to detect a CRC error. A valid packet is sometimes not accepted, but is sent again. The End of Packet of a Valid Incoming Packet Is Sometimes Lost When an incoming packet is terminated by the sym/data/eop/idles pattern, the receiver skips the last data word of the packet. Altera Corporation 3

4 RapidIO Physical Layer MegaCore Function The last word of a valid packet is sometimes lost without retry. The Transmitter's Frame Signal Sometimes Toggles Incorrectly, Causing the Receiver to Reject the Packet When a control symbol is inserted right before a packet, the transmitter extends the internal start-of-packet signal to one more clock cycle. This causes the frame signal to toggle twice at the start of the packet. This issue affects all parallel variations of the A valid packet is sometimes not accepted, but is sent again. 4 Altera Corporation

5 RapidIO Physical Layer MegaCore Function v2.2.1 Issues The Transmitter Sometimes Generates an Incorrect CRC When a Packet Larger Than 80 Bytes Is Followed by a Packet with Zero Latency When a long (larger than 80 bytes) outgoing packet is followed by a packet with zero internal latency, the CRC value gets overwritten by the new packet. The overwritten CRC is inserted at the end of the long packet, causing a CRC error on the receiver. This issue affects all parallel variations of the A valid packet is sometimes not accepted, but is sent again. A Control Symbol Is Sometimes Overwritten Under some circumstances, a control symbol that is scheduled to be transmitted can be overwritten by packet data. This issue affects all parallel variations of the Depending on the type of control symbol that is lost, recoverable or fatal errors can occur, eventually leading to packet loss. Altera Corporation 5

6 RapidIO Physical Layer MegaCore Function An Avoidable Compensation Sequence Insertion Sometimes Causes a Packet to Be Stomped and Retried If a continuous stream of packets is being transmitted and stype0 control symbols (e.g., packet-accepted) become available for transmission at exactly the instant when the start-of-packet control symbol is inserted, the compensation sequence is not inserted between the packets. This can lead to a compensation sequence timeout, which causes the packet to be stomped to allow the forced insertion of a compensation sequence before the 5,000 column limit is reached. This issue causes an occasional recoverable error and the retransmission of a packet. The protocol recovers from the error, the compensation sequence is inserted in time, and no packets are lost. However, some bandwidth is lost. The Header of an Outgoing Packet Is Sometimes Lost If a symbol is inserted between two packets with one clock cycle latency, the packet header is lost. This issue affects all parallel variations of the 6 Altera Corporation

7 RapidIO Physical Layer MegaCore Function v2.2.1 Issues A valid packet is sometimes transmitted without a header, but is recoverable. The Packet Immediately Following a Stomped Packet Sometimes Makes it Through to the Atlantic Interface If a packet is received immediately after a stomped packet, the receiver passes that received packet through to the Atlantic interface. All received packets should be dropped or marked as invalid by asserting the arxerr signal until a restart-from-retry symbol is received. This issue affects all serial variations of the A packet can be received twice. Idle Characters Sometimes Appear in the Start-of-Packet (SOP) Word on the Receiver Signals of the Atlantic Interface If an incoming packet is terminated by the stomp/status/idle pattern, the receiver wrongly treats the idle as the header of the next packet, causing it to be rejected. Altera Corporation 7

8 RapidIO Physical Layer MegaCore Function A valid packet is sometimes not accepted, but is recoverable. The CRC of the Previous Packet Sometimes Appears in the SOP Word on the Receiver Signals of the Atlantic Interface Under some circumstances, the second packet of two consecutive incoming packets has the CRC of the first packet as a SOP word. A valid packet is sometimes not accepted, but is recoverable. A Control Symbol Is Sometimes Lost Under some circumstances, a control symbol that is scheduled to be transmitted can be lost before it is transmitted. 8 Altera Corporation

9 RapidIO Physical Layer MegaCore Function v2.2.1 Issues Depending on the type of control symbol that is lost, recoverable or fatal errors can occur, eventually leading to packet loss. A Control Symbol Is Sometimes Retransmitted Endlessly Under some circumstances, a control symbol can be continually retransmitted every few clock cycles. Depending on the type of control symbol that is repeated, the RapidIO protocol can be, more or less, seriously violated. In the best case scenario, throughput is severely reduced; in the worst case scenario, transmission stops completely. Altera Corporation 9

10 RapidIO Physical Layer MegaCore Function Contact Information Revision History For more information, go to Altera s mysupport website at and click Create New Service Request. Choose the Product Related Request form. Table 1 shows the revision history. Table 1. Revision History Version Date Details of Change 1.0 April 2005 First release of the RapidIO Physical Layer MegaCore function errata sheet for v Innovation Drive San Jose, CA (408) Applications Hotline: (800) 800-EPLD Literature Services: literature@altera.com Copyright 2005 Altera Corporation. All rights reserved. Altera, The Programmable Solutions Company, the stylized Altera logo, specific device designations, and all other words and logos that are identified as trademarks and/or service marks are, unless noted otherwise, the trademarks and service marks of Altera Corporation in the U.S. and other countries. All other product or service names are the property of their respective holders. Altera products are protected under numerous U.S. and foreign patents and pending applications, maskwork rights, and copyrights. Altera warrants performance of its semiconductor products to current specifications in accordance with Altera's standard warranty, but reserves the right to make changes to any products and services at any time without notice. Altera assumes no responsibility or liability arising out of the application or use of any information, product, or service described herein except as expressly agreed to in writing by Altera Corporation. Altera customers are advised to obtain the latest version of device specifications before relying on any published information and before placing orders for products or services. 10 Altera Corporation