Datasheet

 2011-2013 Microchip Technology Inc. DS39995D-page 151
PIC24FV32KA304 FAMILY
15.0 OUTPUT COMPARE WITH
DEDICATED TIMERS
All devices in the PIC24FV32KA304 family feature
3 independent output compare modules. Each of these
modules offers a wide range of configuration and
operating options for generating pulse trains on internal
device events. Also, the modules can produce
Pulse-Width Modulated (PWM) waveforms for driving
power applications.
Key features of the output compare module include:
• Hardware-configurable for 32-bit operation in all
modes by cascading two adjacent modules
• Synchronous and Trigger modes of output
compare operation, with up to 21 user-selectable
Sync/trigger sources available
• Two separate Period registers (a main register,
OCxR, and a secondary register, OCxRS) for
greater flexibility in generating pulses of varying
widths
• Configurable for single pulse or continuous pulse
generation on an output event, or continuous
PWM waveform generation
• Up to 6 clock sources available for each module,
driving a separate internal 16-bit counter
15.1 General Operating Modes
15.1.1 SYNCHRONOUS AND TRIGGER
MODES
By default, the output compare module operates in a
Free-Running mode. The internal 16-bit counter,
OCxTMR, counts up continuously, wrapping around
from FFFFh to 0000h on each overflow, with its period
synchronized to the selected external clock source.
Compare or PWM events are generated each time a
match between the internal counter and one of the
Period registers occurs.
In Synchronous mode, the module begins performing
its compare or PWM operation as soon as its selected
clock source is enabled. Whenever an event occurs on
the selected Sync source, the module’s internal
counter is reset. In Trigger mode, the module waits for
a Sync event from another internal module to occur
before allowing the counter to run.
Free-Running mode is selected by default or any time
that the SYNCSELx bits (OCxCON2<4:0>) are set to
‘00000’. Synchronous or Trigger modes are selected
any time the SYNCSELx bits are set to any value
except ‘00000’. The OCTRIG bit (OCxCON2<7>)
selects either Synchronous or Trigger mode. Setting
this bit selects Trigger mode operation. In both modes,
the SYNCSELx bits determine the Sync/trigger source.
15.1.2 CASCADED (32-BIT) MODE
By default, each module operates independently with
its own set of 16-bit Timer and Duty Cycle registers. To
increase the range, adjacent even and odd numbered
modules can be configured to function as a single
32-bit module. (For example, Modules 1 and 2 are
paired, as are Modules 3 and 4, and so on.) The odd
numbered module (OCx) provides the Least Significant
16 bits of the 32-bit register pairs, and the even
numbered module (OCy) provides the Most Significant
16 bits. Wraparounds of the OCx registers cause an
increment of their corresponding OCy registers.
Cascaded operation is configured in hardware by setting
the OC32 bit (OCxCON2<8>) for both modules.
Note: This data sheet summarizes the features of
this group of PIC24F devices. It is not
intended to be a comprehensive reference
source. For more information, refer to the
“PIC24F Family Reference Manual”,
Section 35. “Output Compare with
Dedicated Timer” (DS39723).