Each interval timer consists of a 16-bit read-only timer counter and a 16-bit write-only timer latch. Data written to the timer is latched into the timer latch, while data read from the timer is the present contents of the timer counter. The latch is also called a prescalar in that it represents the countdown value which must be counted before the timer reaches an underflow (no more counts) condition. This latch (prescalar) value is a divider of the input clocking frequency. The timers can be used independently or linked for extended operations. Various timer operating modes allow generation of long time delays, variable width pulses, pulse trains, and variable frequency waveforms. Utilizing the CNT input, the timers can count external pulses or measure frequency, pulse width, and delay times of external signals. Each timer has an associated control register , providing independent control over each of the following functions: Start/Stop One-shot/continuous PB on/off Force load Toggle/pulse