Hi Qian,
From the subject and description, i am slightly confused if you are using MM9Z1J638 device or MM912J637. Which one? Or both...
Regarding the issue, you say it doesn't go to sleep mode.
Can you tell if the code runaways, or maybe gets stuck somewhere.
Do you do that test with BDM connected or not?
How about using other source of interrupts such as API or RTI?
Regards,
iggi