Abstract: A method, an apparatus, and a computer program are provided to reduce transient current swings during mode transitions. Traditionally, transient supply voltage fluctuations on a chip account for a large portion of the power supply. The number of series inductances and resistances are typically minimized, while adding large decoupling capacitances between the supply voltage and ground. However, situations may arise where reduction of series inductances and resistances cannot be accomplished. Therefore, to assist in controlling the transient current swings, reduction of clocking frequencies are performed in a controlled manner.

Abstract: In the present invention, register values are obtained by scanning, and are then written to one or more trace arrays on the chip. The scan data in the trace arrays is then read out by software. The register scan data can be recirculated among the registers, and addition scans can then be performed and written to the one or more trace arrays.

Abstract: The present invention provides for a circuit for transitioning clocking speeds. A counter is coupled to the clocking means. A comparator is coupled to an output of the counter. A first divider is coupled to the output of the counter. A processor means is coupled to the output of the first divider, thereby lessening current surges.

Abstract: The present invention provides for reducing current spikes in a circuit when changing clocking frequencies. A first frequency is applied to a clock distribution network. A final frequency is selected. The first frequency is applied to a logic element over the clock distribution network. A hold signal is applied to the logic element. The clock rate of the clock distribution network is changed from the first frequency to the final frequency. The hold signal is unapplied to the logic element.