ARM DS-5 Using the Debug Hardware Configuration Utilities

Creating debug hardware target configurations5.16 About adaptive clockingAdaptive clocking enables your debug hardware unit to dynamically adjust the JTAG clock(TCK) following changes to the processor clock (CLK). This is useful when debugging systemwith low power modes and changing clocks in general.Adaptive clocking is intended only for targets that are based on a synthesizable ARM ® processorimplementing RTCK. When a fixed JTAG clock is used, the JTAG clock must be running atmost 1/6 of the processor clock. Using a fixed JTAG clock does not support changes in theprocessor clock speed, which can corrupt the JTAG connection.If you use adaptive clocking, the maximum clock frequency is lower than with non-adaptiveclocking, because of transmission delays, gate delays, and synchronization requirements.5.16.1 See alsoReferenceARM DSTREAM System and Interface Design Reference:• Chapter 2 ARM DSTREAM System Design Guidelines.ARM RVI and RVT System and Interface Design Reference:• Chapter 2 RVI and RVT System Design Guidelines.ARM DUI 0498F Copyright © 2010-2012 ARM. All rights reserved. 5-25ID021112Non-Confidential