Resolved! set timer to interrupt every 500ns(2MHZ)
I am using stm32F103RE with 72mhz timer clock for using timer 1. I set prescalor to 0 and ARR to 35 to make 2MHZ timer interrupt.(72/36=2) to check it I use a variable and add it every 2,000,000 like the code below...I expect it to be added every 1s ...