1. A data processing system comprising: a main application unit for executing a main application having at least one data structure; a memory management unit (MMU) comprising a plurality of first MMU entries for data structures within the main application, the plurality of first MMU entries having access attributes corresponding to a normal mode of execution of the main application; and a data breakpoint implementation system for allowing selection between the normal mode of execution and a debugging mode of execution associated with a selected data structure within the main application, said data breakpoint implementation system creating a first MMU entry and a second MMU entry corresponding to said selected data structure, the second MMU entry being distinct from the first MMU entry for the selected data structure, the second MMU entry having an interrupt triggering sub-entry, where the normal mode of execution is interrupted and the debugging mode of execution for the selected data structure is started upon accessing said second MMU entry.