Altera Corporation

Kian Chin Yap

Kar Keng Chua

Hee Kong Phoon

Phooi Choong Loh

A method to modify a first IC design into a second IC design, the first and second IC designs specifying a common interconnection layer with a plurality of interconnections, is disclosed. The method includes identifying an interconnection from plurality of interconnections within the common interconnection layer. The interconnection is unused for routing signals in the first IC design. The metal layer that is coupled with the identified interconnection is removed from the first IC design to generate a modified design. The identified interconnection of the first IC design is placed into one of an invisible state or a temporarily removed state in the modified design. The metal layer in the modified design is routed for a specific logic gate design. The modified design is then stored as the second IC design.

Method to modify an integrated circuit (IC) design

A mask-programmable logic device includes a macrocell having an external input/output port for 'place-and-route' programming by addition of metallization layers. A programmable 'fixed' layer allows the external input/output port to be isolated from the remainder of the macrocell so that it &#x201c;floats,&#x201d; allowing signals to be routed through the external input/output port when the macrocell is not in use, to reduce routing blockages. The macrocell also may have at least one internal input/output port, potentially connected to different logic circuits, and a programmable &#x201c;fixed&#x201d; layer that can be used to control which internal input/output port is connected to the external input/output port. By thus allowing multiple logic circuits to share a single external input/output port, routing blockages are reduced.

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Lebuh Relai, Malaysia

Kian Chin Yap