AMBA Design Kit Technical Reference Manual - ARM Information ...

AHB Components3.13 Asynchronous AHB-AHB bridgeThe asynchronous AHB-AHB bridge, Ahb2AhbAsync32 and Ahb2AhbAsync64, provides aunidirectional link between two AHB domains with asynchronous clocks. Its functionis to enable a master to access a slave on another bus, with the transfer initiated fromone side only. The asynchronous bridge is not intended for performance applications,because the synchronization logic increases the overhead of a registered bridge design.The asynchronous AHB-AHB bridge has the following features:• 32 or 64-bit data bus• transfer sequences can be locked across the bridge• bursts are split into single transfers to prevent excessive latency from BUSYtransfers• SPLIT and RETRY responses are serviced by the bridge, so remain local to theissuing slave.Figure 3-31 shows the asynchronous AHB-AHB bridge module.Ahb2AhbAsyncAHB1AsynchronousslaveControlsignalsSynchronizationregistersAsynchronousmasterAHB2HCLKSAHB signalsHCLKMFigure 3-31 Asynchronous AHB-AHB bridge module components3.13.1 Programmer's modelThe following sections describe the programming and operation of the asynchronousAHB-AHB bridge:• Reset on page 3-61• Low power operation on page 3-61• Slave responses on page 3-61• Locked transfers on page 3-61.3-60 Copyright © 2003, 2007 ARM Limited. All rights reserved. ARM DDI 0243C