AM2434: Interrupt Service Routine not visited by timer interrupt?

Tool/software:

Hello Specialists,

I was trying to create timer interrupt on AM243x-LP demo-board using a modified mcu_plus_sdk_am243x_10_00_00_20 example project: gpio_led_blink_am243x-lp_r5fss0-0_norotos_ti-arm-clang.

The modified codes are posted as below:

The example.syscfg setting about timer is as below:

After I start the R5F core0 with that modified code, the break-point I set inside the ISR was never triggered. 

There might be several ways to set the Interrupt.

Please help to check what settings were missing for the timer interrupt to be able to visit the ISR.

Thank you very much.    Jason.