Toward Automated ECOs in FPGAs

Engineering change orders (ECOs), which are used to apply late-stage specification changes and bug fixes, have become an important part of the field-programmable gate array design flow. ECOs are beneficial since they are applied directly to a placed-and-routed netlist which preserves most of the engineering effort invested previously. Unfortunately, designers often apply ECOs in a manual fashion which may have an unpredictable impact on the design's final correctness and end costs. As a solution, this paper introduces an automated method to tackle the ECO problem. This paper uses a novel resynthesis technique which can automatically update the functionality of a circuit by leveraging the existing logic within the design, thereby removing the inefficient manual effort required by a designer. The technique presented in this paper is robust enough to handle a wide range of changes. Furthermore, the technique can successfully make late-stage functional changes while minimally perturbing the placed-and-routed netlist: something that is necessary for ECOs. Also, this technique does this with a minimal impact on the circuit performance where on average over 90% of the placement and routing wires remain unchanged.