Runtime reconfiguration of reconfigurable circuits

A circuit comprising:

• a primary function block configured to implement a function and having first built-in self-test (BIST) circuitry configured to determine whether the primary function block is defective;
• a redundant function block having second BIST circuitry, the redundant function block configured to selectively implement the function in place of the primary function block if the primary block is determined to be defective;
• and
• a sequencer configured to operate the first BIST circuitry of the primary and redundant function blocks and to facilitate replacement of the primary function block with the redundant function block based at least in part on a result of a test run of the first BIST circuitry of the primary function block.

A method comprising:

• providing a circuit including a plurality of primary function blocks and a plurality of redundant function blocks;
• running a production test on built-in self-test (BIST) circuitry of the plurality of primary function blocks;
• determining whether one or more of the primary function blocks are defective based at least in part on a result of the production test;
• and
• accepting the circuit for distribution if the result indicates a ratio of non-defective primary function blocks to redundant function blocks allows rerouting of I/O and internal signals to facilitate replacement of defective primary function blocks by redundant function blocks.