This TTC module provides three independent timer counter modules that can each be clocked using either the system clock or an externally derived clock. The clock input to each counter can be independently prescaled (divided by between 2 and 65,536). Counters can be set to decrement or increment. Each external clock input is synchronised with the system clock before being applied to its timer counter. The pulse width of each external clock is measured by counting the system clock cycles into its event timer register. Each of the timer counters can be programmed to generate interrupt pulses at regular timed intervals or on counter overfl ow (when the count exceeds 216).