Patent ID: 8826079

Claim:
A data processing apparatus comprising: at least one circuit block that is accessible for debugging by a debugger coupled to the data processing apparatus, each of said at least one circuit block having a set of debug status registers associated therewith, said set of debug status registers including a debug event register which is set by the circuit block to indicate occurrence of a debug event within the circuit block; debug interface circuitry via which said debugger connects to said data processing apparatus, and configured to interface said debugger with said set of debug status registers for each of said at least one circuit block; the debug interface circuitry including at least a first portion which is in a first power domain that remains in a fully powered state whilst said debugger is connected to said debug interface circuitry; said set of debug status registers associated with each of said at least one circuit block being in a second power domain which is allowed to transition between said fully powered state and at least one low power state whilst said debugger is connected to said debug interface circuitry, content of said debug status registers only being accessible to the debugger via the debug interface circuitry when said second power domain is in said fully powered state; and at least one debug attention register provided within said first power domain in association with said first portion of the debug interface circuitry, said at least one debug attention register configured to provide information identifying whether the debug event register provided within the set of debug status registers for any of said at least one circuit block is set; whereby polling performed by the debugger to detect debug events is performed in respect of said at least one debug attention register, and only if a result of such polling indicates that the debug event register provided within the set of debug status registers for any of said at least one circuit block is set is polling of the debug status registers then performed by the debugger to identify the debug event.