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

AHB-Lite OverviewA.2 AHB-Lite masterAn AHB-Lite master has the same signal interface as a full AHB bus master, except thatit does not support HBUSREQx and HGRANTx.The Lock functionality is still required because the master might be performing atransfer to a multi-port slave. The slave must be given an indication that no othertransfer should occur to the slave when the master requires locked access.An AHB-Lite master is not required to support either the SPLIT or RETRY responseand only the OKAY and ERROR responses are required, so the AHB-Lite masterinterface does not require the HRESP[1] input.A.2.1AHB-Lite advantagesThe advantage of using the AHB-Lite protocol is that the bus master does not have tosupport the following cases:• Losing ownership of the bus. The clock enable for the master can simply bederived from the HREADY signal on the bus.• Early terminated bursts. There is no requirement for the master to rebuild a burstdue to early termination, because the master always has access to the bus.• SPLIT or RETRY transfer responses. There is no requirement for the master toretain the address of the last transfer to be able to restart a previous transfer.A.2.2AHB-Lite conversion to full AHBA standard wrapper is available to convert an AHB-Lite master to make it a full AHBmaster. This wrapper adds support for the features described in AHB-Lite advantages.Because the AHB-Lite master has no bus request signal available, the wrapper generatesthis directly from the HTRANS signals.ARM DDI 0243C Copyright © 2003, 2007 ARM Limited. All rights reserved. A-5