Applies to: AHB At the start of the address phase of every transfer the arbiter will sample the HLOCK signal of the master that is about to start driving the address bus and if HLOCK is asserted at this point then HMASTLOCK will be asserted by the arbiter for the duration of the address phase of the transfer. FROM: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/583.