Abstract: A program-controlled unit has debug resources for monitoring the operations proceeding within the program-controlled unit. The program-controlled unit described is distinguished by the fact that the debug resources contain a CPU, and/or that a portion of the debug resources is provided for monitoring the operations proceeding within the remainder of the debug resources. Debug resources constructed in this way make it possible for errors occurring in program-controlled units to be localized and eliminated rapidly and simply under all circumstances.

Abstract: For controlling frequency and phase of an output clock signal dependent on a reference signal, a digital phase locked loop comprises a ring oscillator connected to a switch-over unit for generating the output clock signal. The ring oscillator has a plurality of serially arranged delay units. A phase comparator for comparing the phase of the reference signal and of the output clock signal. At least one switchable frequency divider unit is provided between the phase comparator and the output clock signal. A control unit controls the ring oscillator frequency by cut-in or cut-outs of delay units with the assistance of the switchover unit.

Abstract: Several users emit their own selection signal and clock signal to their respective selection circuits. The selection circuits send selection criteria to all other selection circuits and the clock switching stage. The selection circuit sends an activity signal to a digital circuit based on the allocated user's selection signal, the selection criteria of all the other selection circuits and the selected clock signal.