Network media access controller embedded in a programmable logic device—receive-side client interface

A receive-side client interface for a media access controller, comprising:

• a media access controller core including a receive engine;
• and
• a receive-side datapath coupled to the media access controller core, the receive-side datapath including a first set of registers, a second set of registers and a third set of registers, the first set of registers clocked responsive to a first clock signal, the second set of registers clocked responsive to a second clock signal and coupled to receive a select mode signal, the select mode signal being enabled to select either a first data width or a second data width, the third set of registers clocked responsive to a third clock signal, the second clock signal being an undivided version of the first clock signal, the third clock signal being a divided version of the first clock signal;
• wherein the media access controller is embedded in an integrated circuit having programmable logic, the programmable logic capable of operating at the third clock signal frequency;
• and
• wherein the first set of registers and a first portion of the second set of registers are multiplexer select registers and in combination are enabled to provide a multiplexer select signal.