System Timer - Step 1 & 2

As earlier mentioned, the first 2 steps in creating a PAC are...

1. Reading the concerned datasheet segment of the ARM reference manual and understanding it.
2. Outlining all the registers concerned. Outlining the fields within each register. Listing all the allowed values of each register field.

I can't help you do step 1.
Here is how I did step 2:

Registers :