The present invention relates to a bridge for interfacing buses within an embedded system. There is provided a method of interfacing a first bus and a second bus operating at different speeds, the method includes counting a match value assigned to a predetermined peripheral device among peripheral devices connected to the second bus for each cycle of a clock signal received from the first bus, and keeping a read state or a write state for the predetermined peripheral device by continuously outputting a read signal or a write signal for the predetermined peripheral device to the second bus, during the counting of the match value. According to the present invention, it is not necessary to operate depending on a peripheral device operating at the lowest speed among peripheral devices, and not necessary to add wrappers to the peripheral devices, by employing the AHB-to-ISA bridge variably adjusting the output times of output signals to an ISA bus.