User may use Watchpoints to halt on multiple read and/or write accesses in memory. For how to use it, please view page DM259-268 in debugger manual: http://cache.freescale.com/files/soft_dev_tools/doc/user_guide/HC12ENGINEUG.pdf
Hi,
I never used this board, but as far I know this must support watchpoints. In this case you can setup a watchpoint on the entire RAM zone.
Regards,
Marius