Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet

Product codes
AT91SAM9N12-EK
Page of 248
Tightly-Coupled Memory Interface 
5-32
Copyright © 2001-2003 ARM Limited. All rights reserved.
ARM DDI0198D
5.9
TCM clock gating
If the ARM926EJ-S processor is not currently running code from a TCM region, the 
idle signal for that TCM (DRIDLE for DTCM, IRIDLE for ITCM) is asserted. This 
indicates that a TCM access will not be performed in that cycle, enabling you to stop 
the TCM clock. If no clock stopping is required, you can ignore the idle signals.
You can also use the idle signal to disable power to the RAMs if you require more 
stringent power control. Removing the RAM power invalidates the RAM contents so 
you must only do this if the TCMs are not being used and do not contain valid data.