hi,

i was thinking of a way how to determine the period of a slow pulse. assuming, the rising edge would be used as the starting and end points, the edge triggered exernal interrupt would start a timer and the next edge would reset the timer to zero.

the actual time taken from the first rising edge and second rising edge is the pulse period, right?

the problem actually comes out when long periods are to be determined (low frequency pulses). the timer would eventually and continuously overflow.

i tried to increment adjacent registers, but it seems that when more registers are used, "the more vague" the actual time is.

is there another way of dealing with this problem?