The bi-directional AHB/AHB Bridge is used to interconnect high-speed and low-speed AMBA AHB buses. The bridge supports synchronous clocks with any frequency ratio between the two interconnected buses.
Internally, the bridge consists of two uni-directional AHB to AHB bridges and additional logic to synchronize signals (other than AHB signals) crossing high-speed bus and low-speed bus clock domains.
A high-speed AMBA AHB bus hosting e.g. LEON3 CPUs and a external memory controller can be interconnected with a with a low-speed AHB bus hosting e.g. hosting slow communication IP-cores.