The purpose of the digital circuit implemented in each bitstream is to test the function of each specific resource in parallel, using the test patterns. Each bitstream contains an equal number of digital test circuits for each of the resources, although this number will vary according to the width of the communication bus between the FMother and the FUT Board since bus width determines the number of resource units which can be tested simultaneously.
Thus, for each resource unit a number of entry/exit lines are required in each digital circuit located in the unit, and these are used to insert the pattern data and capture the results which are then stored and compared on the FMother