A program-controlled unit includes a core for executing the program to be executed by the program-controlled unit, and debug resources for tracking and influencing the operations proceeding within the core. The program-controlled unit is distinguished by the fact that the debug resources are able also to influence other components of the program-controlled unit and/or the cooperation of these components with one another and/or with the core. Such action makes it possible to avoid to the greatest possible extent, in a simple manner, the situation wherein disturbances or errors that do not occur in normal operation of the program-controlled unit occur during the debugging or emulation of the program-controlled unit, and/or wherein errors that occur in normal operation of the program-controlled unit do not occur during the debugging or emulation of the program-controlled unit.
Watchdog instructions embedded within the actual microcode that is executed by the processor. Accordingly, as the processor reads and executes the microcode, the processor occasionally encounters the watchdog instruction. Each time the processor executes the watchdog instruction, the processor generates a watchdog signal. A watchdog signal detection circuit detects the presence of the periodic signal. If the watchdog signal has not occurred when expected, then some instability has likely occurred. Accordingly, the watchdog signal detection circuit causes some corrective action to be taken when a watchdog signal is not detected when expected. Such corrective action may include, for example, rebooting the system or resetting one or more modules of the system. The inclusion of the watchdog instruction within the microcode increases the chance that the watchdog signal will be an accurate predictor of system stability.
