The input capture module has the task of capturing the curent value of the timer counter upon an input event. This module is mainly used for the frequency or time period measurements and pulse measurements (e.g. mean count rate measurement). Microcontroller dsPIC30F4013 contains 4 input capture modules, whereas dsPIC30F6014A contains 8 input capture modules. The input capture module has multiple operatig modes selectable via the ICxCON register (control bit ICM<2:0>):
Select by external input signal mode,
Interrupt by external input signal mode.
The input capture module contains a four-level FIFO buffer. By setting the control bits a user can select the number of captures from the counter before the input capture module generates an interrupt request.
Fig. 5-1 Functional diagram of the inpuit capture module