Mode 2: On every rising edge seen by the external pin, this mode records the number of clock cycles (clock frequency determined by TimerClockBase/TimerClockDivisor) between this rising edge and the previous rising edge. The value is updated on every rising edge, so a read returns the time between the most recent pair of rising edges.
In this 32-bit mode, the Control processor must jump to an interrupt service routine to record the time, so small errors can occur if another interrupt is already in progress. The possible error sources are:
Note that the minimum measurable period is limited by the edge rate limit discussed in Section 2.10.2.
Writing a value of zero to the timer performs a reset. After reset, a read of the timer value will return zero until a new edge is detected. If a timer is reset and read in the same function call, the read returns the value just before the reset.
Mode 3 is the same except that falling edges are used instead of rising edges.