ARM DS-5 Using the Debug Hardware Configuration Utilities

Creating debug hardware target configurationsStopped Controls the state of a processor after a reset. It is only available fordevices that are capable of running (such as ARM processors). Eachdevice on the scan chain does not have to be set to the same value, soit is valid to have one processor running and another stopped.NoteIf you want to connect to a running target without performing a reset and withoutstopping the target, you must do both of the following:• In debug hardware, set the Post Reset State to Running.• In your debugger, connect using the No Reset/No Stop connection mode.Soft TAP reset on JTAG sync lossIn some situations, such as a processor entering low power mode, thesynchronization between the debug unit and the TAP controller in the JTAGsystem can be lost. This can result in invalid values for the debug status registerbeing read. To regain the synchronization, a soft TAP reset must be performed toget the TAP controller into a known state.If Soft TAP reset on JTAG sync loss is checked, a soft TAP reset is performed toget the TAP controller into a known state if the debug unit reads invalid values forthe debug status register.Software breakpoint modeIf supported by your processors, this control enables you to configure how thedebug hardware unit handles software breakpoints. Select the required breakpointmode:AUTO This is the default mode for all templates:• If the processor being debugged supports BKPT instructions,debug hardware automatically uses the BKPT instruction forsoftware breakpoints.• Only one watchpoint resource is used for multiple softwarebreakpoints. Therefore, if the processor being debugged does notsupport BKPT instructions, debug hardware uses the watchpointunit resource when you set a software breakpoint. The debughardware unit automatically frees the watchpoint unit resourcewhen all software breakpoints are cleared.NONE When this mode is selected, you cannot set software breakpoints. Ifyou attempt to set a software breakpoint, debug hardware gives anerror message telling you that there are no free resources to set thebreakpoint.WATCHPOINTThis mode instructs debug hardware to use one watchpoint unit toprovide software breakpoint instructions, whether or not the processorbeing debugged supports BKPT instructions. Select this option if theprocessor supports BKPT instructions but you want to use a watchpointunit.BKPT This mode instructs debug hardware to use the BKPT instruction toprovide software breakpoint instructions, whether or not the processorsupports this instruction. Select this option if you want to make surethat no watchpoints are used.ARM DUI 0498F Copyright © 2010-2012 ARM. All rights reserved. 5-29ID021112Non-Confidential