Abstract: In a method and apparatus for setting an address range for a computer expansion card of a computer system, the computer system is first controlled so as to execute a write operation which involves a series of addresses within the address range to be assigned to the computer expansion card. A linear feedback shift register receives the series of addresses from address lines of the computer system and derives a code output from the series of addresses. A code detecting unit receives the code output of the linear feedback shift register and compares the code output with a predetermined code. The code detecting unit generates a match signal whenever the code output matches with the predetermined code. An address register is activated by the match signal so as to store most significant bits of the address range to be assigned to the computer expansion card therein. The most significant bits are common to all of the addresses within the address range.