Nowadays electronic devices are used in a huge number of applications, from entertainment market to military equipment, from mobile phones to satellites. Each application has its own requirements and constraints depending on its purpose. One particular kind of applications is the one called mission critical that is characterized by a large amount of money that could be lost if something goes wrong. As an example this is the case of satellites that cannot be repaired or returned for maintenance if some parts stop working. When electronic device, and in particular FPGAs, are used in mission critical applications their reliability requires a special attention, therefore a key aspect of them is the capability to tolerate faults. When FPGAs operate in harsh environment, like in space, both temporary and permanent faults can occur due to radiation. The on-line testing technique involves a testing circuit that is capable to test its own used resources. In this work a design and implementation of a routing algorithm to maximize fault coverage of permanent faults is presented
