Arria V Hard Processor System Technical Reference Manual

ID 683011
Date 12/02/2022
Public
Document Table of Contents

24.4.4. Loading the Timer Countdown Value

When a timer counter is enabled after being reset or disabled, the count value is loaded from the timer1loadcount register; this occurs in both free-running and user‑defined count modes. †

When a timer counts down to 0, it loads one of two values, depending on the timer operating mode: †

  • User-defined count mode—timer loads the current value of the timer1loadcount register. Use this mode if you want a fixed, timed interrupt. Designate this mode by writing a 1 to the timer1_mode bit of the timer1controlreg register. †
  • Free-running mode—timer loads the maximum value (0xFFFFFFFF). The timer max count value allows for a maximum amount of time to reprogram or disable the timer before another interrupt occurs. Use this mode if you want a single timed interrupt. Enable this mode by writing a 0 to the timer1_mode bit of the timer1controlreg register. †