This post is related to the previuos one MPC5644A System Timer Module problem.
Thank you so much for your answer, I tried the solution you proposed and worked ok!
I miss understood what was stated in the Reference manual that the Sytem Timer Module counter roll over automatically from 0xFFFFFFFF to 0x00000000 and so I thought that every time one comparator is equal to the counter an interrupt is raised...
moreover I just tried to use the PIT with success, the purpose to use this timer is to have a basic tick counter for a scheduler and I thought the best way was using the STM..anyway, I think I will use the PIT.
Thank you again,
have a good day.