Multiple data rates in programmable logic device serial interface

A serial interface for use in a programmable logic device, said serial interface comprising:

• a plurality of groups of two channels, each channel comprising a physical coding sublayer module and a physical medium attachment module;
• wherein, in each of said groups:
• the physical medium attachment module in a first one said channels supports a first maximum physical medium attachment data rate;
• the physical medium attachment module in a second one of said channels supports a second maximum physical medium attachment data rate lower than said first physical medium attachment data rate;
• and
• each of said physical coding sublayer modules supports a predetermined maximum physical coding sublayer data rate lower than said first maximum physical medium attachment data rate;
• each of said groups further comprising:
• a selector for selectably connecting the physical coding sublayer module in said second one of said channels to one of (a) said physical medium attachment module in said first one of said channels that supports a first maximum physical medium attachment data rate, and (b) said physical medium attachment module in said second one of said channels that supports said second maximum physical medium attachment data rate;
• whereby:
• each of said groups is selectably operable as one of (a) one channel at said first maximum physical medium attachment data rate, and (b) two channels at said second maximum physical medium attachment data rate.