PXS20RM Datasheet, PDF (658/1368 Pages) Freescale Semiconductor, Inc – PXS20 Microcontroller

Flexible Motor Control Pulse Width Modulator Module (FlexPWM)
Submodule0 counter (PWM generation)
VAL5
VAL4
VAL3
VAL2
VAL1
VAL0
Submodule1 counter
Output Triggers
Figure 25-9. Multiple Output Triggers Over Several PWM Cycles
25.3.2.6 Enhanced Capture Capabilities (E-Capture)
When a PWM pin is not being used for PWM generation, it can be used to perform input captures. Recall
that for PWM generation BOTH edges of the PWM signal are specified via separate compare register
values. When programmed for input capture, both of these registers work on the same pin to capture
multiple edges, toggling from one to the other in either a free running or one-shot fashion. By simply
programming the desired edge of each capture circuit, period and pulse width of an input signal can easily
be measured without the requirement to re-arm the circuit. In addition, each edge of the input signal can
clock an 8 bit counter where the counter output is compared to a user specified value (EDGCMP). When
the counter output equals EDGCMP, the value of the submodule timer is captured and the counter is
automatically reset. This feature allows the module to count a specified number of edge events and then
perform a capture and interrupt. Figure 25-10 illustrates some of the functionality of the E-Capture circuit.
25-12
PXS20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor