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AR# 18967

OPB EMAC Lite v1.01a - Release Notes for opb_ethernetlite_v1_01_a in EDK 6.2.02i

Description

General Description: 

This Answer Record describes improvements made in the OPB EMAC Lite (opb_ethernetlite_v1_01_a) in EDK 6.2.02i.

Solution

A new version of the OPB Ethernet Lite MAC (v1.01a) is introduced in EDK 6.2.02i to reflect the following changes. The new version is opb_ethernetlite_v1_01_a. 

 

The following bug fixes and enhancements are in the EDK 6.2.02i release of the OPB Ethernet Lite MAC v1.01a Core: 

 

- The core version name was changed from opb_ethernetlite_v1_00_a to opb_ethernetlite_v1_01_a to reflect the following changes. 

 

- The transmit and receive data memory was expanded to allow for a ping and pong buffer for each function. The core can now allow access to one transmit and receive frame while another transmit and receive frame is being transmitted or received. This affects the parameters and memory map, so please refer to the updated data sheet for more information. 

 

- An interrupt signal was added to indicate transmit or receive done. Independent and global enable/disable functions are provided. This affects the memory map as well as port mapping, so please refer to the updated data sheet for more information. 

 

- The core was enhanced to increase the randomness of the collision backoff period during half duplex operation. This change does not affect the user interface. 

 

- The COREGen asynchronous FIFO netlist files used by this core have been updated to a more recent version. Also generated the FIFOs without RPMs. RPMs are not required to meet timing and increased difficulty of place and route. This change does not affect the user interface. 

 

- Added support for qvirtex2, qrvirtex2, and Virtex-4 device families. 

 

- Enhanced signal timing to ensure that PHY_tx_en signal always goes active on the same clock as the transmit data. This change does not affect the user interface. 

 

- Reduced latency in response with JAM to a collision in half duplex mode. Also increased accuracy of length of JAM pattern transmitted. Fixed bug where previously JAM may not complete if PHY_col goes inactive before the end of the JAM sequence. Also fixed bug that prevented completion of preamble and SFD field if collision occurred during that period. This change does not affect the user interface. 

 

- Fixed bug that prevented receiving a frame with an extra nibble after a correct CRC field. This change does not affect the user interface. 

 

- Increased accuracy of the interframe gap period. This change does not affect the user interface. 

 

- Fixed bug that caused receive packets with bad or missing End Of Stream characters to be accepted as good frames. These frames will now be rejected. This change does not affect the user interface. 

 

- Fixed a bug so that maximum number of transmit retries to a collision is 15 for a total attempts of 16, which is one less than before. This change does not affect the user interface. 

 

- Improved design so that core can be operated with an OPB clock as slow as 50 MHz while operating at 100 Mbs on the Ethernet bus. 

 

- Fixed a bug with inserting padding. The correct number of bytes is now always inserted for padding. 

 

- Fixed a bug that could cause a receive lock-up condition. 

 

- Changed C_DEV_ADDR_DECODE_WIDTH to 19 in XEMAC from 17.

AR# 18967
Date Created 09/03/2007
Last Updated 05/16/2014
Status Archive
Type General Article