debug services certain system malfunctions can disrupt the running of this software to an extent that makes these debug services unusable examples of this are bus hangs and errors within the application 39 s interface drivers debug using a dedicated interface is typically used during the development and bring up phases of a product 39 s lifecycle and in many instances can be minimally intrusive having little to no effect on the normal system operation when the system is running the application it generally provides a means to find and fix problems that can make the target system ts inoperable such problems include bus hangs power management failures phantom resets and other fatal errors these are capabilities that are not generally available in the set of debug capabilities provided by applications interface they may provide the ability to view of the state of clock and reset logic voltage power domains power management logic bus control logic and the like in addition these capabilities may provide very fine granularity of controlling the execution of cpu cores for instance a processor with multiple cores will likely support a debug control function that can be used to halt and advance the state of those cores instruction by instruction it may also provide a means to modify the state of caches override the state of various clock reset voltage and power domains and modify the operational state of processing elements in the processor the dedicated debug interface is often called a debug access port dap and one.