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

AHB Components3.10 APB bridgeThe AHB-APB bridge is an AHB slave, providing an interface between the high-speedAHB domain and the low-power APB domain. Read and write transfers on the AHB areconverted into corresponding transfers on the APB through a master interface. Becausethe APB is not pipelined, wait states are added during transfers to and from the APBwhen the AHB is required to wait for the APB protocol. The default configuration is 16slots.In this release of ADK there are two versions of the APB bridge.3.10.1 Ahb2Apb bridgeThe Ahb2Apb bridge consists of the following:• It is the original ADK bridge.• Instanced within EASY systems, and is used in those examples.• Supports APB 2.0 only.• Always returns an OKAY response.• Peripheral slot size decoded from HADDR[27:24], and is 16MB.• Uses MuxP2B peripheral to bridge multiplexor.Figure 3-14 shows the Ahb2Apb bridge module diagram.Figure 3-14 Ahb2Apb bridge module3-40 Copyright © 2003, 2007 ARM Limited. All rights reserved. ARM DDI 0243C