METHOD FOR DYNAMICALLY CHANGING MICROPROCESSOR, CLOCK CONTROL CIRCUIT AND INTERNAL MICROPROCESSOR CLOCK SIGNAL FREQUENCY

摘要

PROBLEM TO BE SOLVED: To provide a clock control system to dynamically change an internal clock frequency of a microprocessor. ;SOLUTION: A clock control system contains a delay sensing circuit 204 which is connected to a clock switching circuit. One pair of tap points is arranged to an output of a delay element which is selected along a delay chain. Each tap point is connected to its own input line of a latching unit through a buffer unit. During an processor operation, an external clock generator gives a clock signal to an input of the delay chain, and the signal is sequentially transferred through each delay element in the delay chain. When a specific rise or fall edge of the clock signal is transferred through the delay chain, corresponded signal transition then appears on the tap point. When high transfer delay is detected, an internal clock frequency is reduced, and when low transfer delay is detected, the internal clock frequency is increased.;COPYRIGHT: (C)1996,JPO