PIC18F2480/2580/4480/4580
TABLE 16-1: CCP MODE – TIMER
RESOURCE
CCP/ECCP Mode
16.1 CCP Module Configuration
Each Capture/Compare/PWM module is associated
with a control register (generically, CCPxCON) and a
data register (CCPRx). The data register, in turn, is
comprised of two 8-bit registers: CCPRxL (low byte)
and CCPRxH (high byte). All registers are both
readable and writable.
Timer Resource
Capture
Compare
PWM
Timer1 or Timer3
Timer1 or Timer3
Timer2
The assignment of a particular timer to a module is
determined by the Timer to CCP enable bits in the
T3CON register (Register 15-1). Both modules may be
active at any given time and may share the same timer
resource if they are configured to operate in the same
mode (Capture/Compare or PWM) at the same time.
The interactions between the two modules are
summarized in Figure 16-1 and Figure 16-2.
16.1.1
CCP MODULES AND TIMER
RESOURCES
The CCP modules utilize Timers 1, 2 or 3, depending
on the mode selected. Timer1 and Timer3 are available
to modules in Capture or Compare modes, while
Timer2 is available for modules in PWM mode.
TABLE 16-2: INTERACTIONS BETWEEN CCP1 AND ECCP1 FOR TIMER RESOURCES
CCP1 Mode ECCP1 Mode
Interaction
Capture
Capture
Each module can use TMR1 or TMR3 as the time base. Time base can be different for
each CCP.
Capture
Compare
CCP1 can be configured for the Special Event Trigger to reset TMR1 or TMR3
(depending upon which time base is used). Automatic A/D conversions on trigger event
can also be done. Operation of CCP1 could be affected if it is using the same timer as a
time base.
Compare
Compare
Capture
CCP1 can be configured for the Special Event Trigger to reset TMR1 or TMR3
(depending upon which time base is used). Operation of CCP1 could be affected if it is
using the same timer as a time base.
Compare
Either module can be configured for the Special Event Trigger to reset the time base.
Automatic A/D conversions on ECCP1 trigger event can be done. Conflicts may occur if
both modules are using the same time base.
Capture
Compare
PWM(1)
PWM(1)
PWM(1)
PWM(1)
PWM(1)
Capture
Compare
PWM
None
None
None
None
Both PWMs will have the same frequency and update rate (TMR2 interrupt).
Note 1: Includes standard and Enhanced PWM operation.
DS39637D-page 168
© 2009 Microchip Technology Inc.
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