Abstract: The present invention relates to a method for the parallel production of circuitry and software for a customised integrated circuit, primarily an ASIC-type circuit, mounted on a printed board assembly or circuit board (300). The method comprises connecting a programmable logic circuit (345) which replaces the customised integrated circuit during the development phase. The programmable logic circuit (345) is mounted on the secondary side of the circuit board (300) and its connections are passed through (330) the circuit board (300) to the circuits (305, 310) and components (320, 325) to which the customised integrated circuit will be connected.The invention also relates to a method and to a device respectively for developing and verifying customised integrated circuits per se. In this case, a programmable logic circuit designed as a logic analyser is mounted on the secondary side of the circuit board and connected to the customised integrated circuit through the board.