Microchip Technology DV164136 Data Sheet
PIC18F8722 FAMILY
DS39646C-page 180
© 2008 Microchip Technology Inc.
17.1
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.
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.
17.1.1
CCP MODULES AND TIMER
RESOURCES
RESOURCES
The CCP/ECCP modules utilize Timers 1, 2, 3 or 4,
depending on the mode selected. Timer1 and Timer3
are available to modules in Capture or Compare
modes, while Timer2 and Timer4 are available for
modules in PWM mode.
depending on the mode selected. Timer1 and Timer3
are available to modules in Capture or Compare
modes, while Timer2 and Timer4 are available for
modules in PWM mode.
TABLE 17-1:
CCP MODE – TIMER
RESOURCE
RESOURCE
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). Depending on the
configuration selected, up to four timers may be active
at once, with modules in the same configuration
(Capture/Compare or PWM) sharing timer resources.
The possible configurations are shown in Figure 17-1.
determined by the Timer to CCP enable bits in the
T3CON register (Register 15-1). Depending on the
configuration selected, up to four timers may be active
at once, with modules in the same configuration
(Capture/Compare or PWM) sharing timer resources.
The possible configurations are shown in Figure 17-1.
17.1.2
ECCP2 PIN ASSIGNMENT
The pin assignment for ECCP2 (Capture input,
Compare and PWM output) can change, based on
device configuration. The CCP2MX Configuration bit
determines which pin ECCP2 is multiplexed to. By
default, it is assigned to RC1 (CCP2MX = 1). If the
Configuration bit is cleared, ECCP2 is multiplexed with
RE7 in Microcontroller mode, or RE3 in all other
modes.
Compare and PWM output) can change, based on
device configuration. The CCP2MX Configuration bit
determines which pin ECCP2 is multiplexed to. By
default, it is assigned to RC1 (CCP2MX = 1). If the
Configuration bit is cleared, ECCP2 is multiplexed with
RE7 in Microcontroller mode, or RE3 in all other
modes.
Changing the pin assignment of ECCP2 does not auto-
matically change any requirements for configuring the
port pin. Users must always verify that the appropriate
TRIS register is configured correctly for ECCP2
operation regardless of where it is located.
matically change any requirements for configuring the
port pin. Users must always verify that the appropriate
TRIS register is configured correctly for ECCP2
operation regardless of where it is located.
FIGURE 17-1:
CCP AND TIMER INTERCONNECT CONFIGURATIONS
CCP Mode
Timer Resource
Capture
Compare
PWM
Timer1 or Timer3
Timer1 or Timer3
Timer2 or Timer4
Timer1 or Timer3
Timer2 or Timer4
TMR1
CCP5
TMR2
TMR3
TMR4
CCP4
ECCP3
ECCP2
ECCP1
TMR1
TMR2
TMR3
CCP5
TMR4
CCP4
ECCP3
ECCP2
ECCP1
TMR1
TMR2
TMR3
CCP5
TMR4
CCP4
ECCP3
ECCP2
ECCP1
TMR1
TMR2
TMR3
CCP5
TMR4
CCP4
ECCP3
ECCP2
ECCP1
T3CCP<2:1> = 00
T3CCP<2:1> = 01
T3CCP<2:1> = 10
T3CCP<2:1> = 11
Timer1 is used for all Capture
and Compare operations for
all CCP modules. Timer2 is
used for PWM operations for
all CCP modules. Modules
may share either timer
resource as a common time
base.
and Compare operations for
all CCP modules. Timer2 is
used for PWM operations for
all CCP modules. Modules
may share either timer
resource as a common time
base.
Timer3 and Timer4 are not
available.
available.
Timer1 and Timer2 are used
for Capture and Compare or
PWM operations for ECCP1
only (depending on selected
mode).
for Capture and Compare or
PWM operations for ECCP1
only (depending on selected
mode).
All other modules use either
Timer3 or Timer4. Modules
may share either timer
resource as a common time
base if they are in Capture/
Compare or PWM modes.
Timer3 or Timer4. Modules
may share either timer
resource as a common time
base if they are in Capture/
Compare or PWM modes.
Timer1 and Timer2 are used
for Capture and Compare or
PWM operations for ECCP1
and ECCP2 only (depending
on the mode selected for each
module). Both modules may
use a timer as a common time
base if they are both in
Capture/Compare or PWM
modes.
for Capture and Compare or
PWM operations for ECCP1
and ECCP2 only (depending
on the mode selected for each
module). Both modules may
use a timer as a common time
base if they are both in
Capture/Compare or PWM
modes.
The other modules use either
Timer3 or Timer4. Modules
may share either timer
resource as a common time
base if they are in Capture/
Compare or PWM modes.
Timer3 or Timer4. Modules
may share either timer
resource as a common time
base if they are in Capture/
Compare or PWM modes.
Timer3 is used for all Capture
and Compare operations for
all CCP modules. Timer4 is
used for PWM operations for
all CCP modules. Modules
may share either timer
resource as a common time
base.
and Compare operations for
all CCP modules. Timer4 is
used for PWM operations for
all CCP modules. Modules
may share either timer
resource as a common time
base.
Timer1 and Timer2 are not
available.
available.