PIC18F6585 Datasheet, PDF (173/496 Pages) Microchip Technology – 64/68/80-Pin High-Performance, 64-Kbyte Enhanced Flash Microcontrollers with ECAN Module

PIC18F6585/8585/6680/8680
15.3 Compare Mode
In Compare mode, the 16-bit CCPRx register value is
constantly compared against either the TMR1 register
pair value or the TMR3 register pair value. When a
match occurs, the CCPx pin can have one of the
following actions:
• Driven high
• Driven low
• Toggle output (high-to-low or low-to-high)
• Remains unchanged
The action on the pin is based on the value of control
bits, CCPxM3:CCPxM0. At the same time, interrupt
flag bit, CCPxIF, is set.
When configured to drive the CCP pin, the CCP1 pin
cannot be changed; CCP1 module controls the pin.
15.3.1 CCP PIN CONFIGURATION
The user must configure the CCPx pin as an output by
clearing the appropriate TRIS bit.
By default, the CCP2 pin is multiplexed with RC1.
Alternately, it can also be multiplexed with either RB3
or RE7. This is done by changing the CCP2MX
configuration bit.
Note:
Clearing the CCPxCON register will force
the CCPx compare output latch to the
default low level. This is not the data latch.
15.3.2 TIMER1/TIMER3 MODE SELECTION
The timer used with each CCP module is selected in
the T3CCP2:T3CCP1 bits of the T3CON register.
Timer1 and/or Timer3 must be running in Timer mode,
or Synchronized Counter mode, if the CCP module is
using the compare feature. In Asynchronous Counter
mode, the compare operation may not work.
15.3.3 SOFTWARE INTERRUPT MODE
When generate software interrupt is chosen, the CCPx
pin is not affected. Only a CCP interrupt is generated (if
enabled).
15.3.4 SPECIAL EVENT TRIGGER
In this mode, an internal hardware trigger is generated
which may be used to initiate an action.
The special event trigger output of CCP1 resets either
the TMR1 or TMR3 register pair. This allows the CCPR1
register to effectively be a 16-bit programmable period
register for TMR1 or TMR3.
Additionally, the CCP2 special event trigger will start an
A/D conversion if the A/D module is enabled.
Note:
The special event trigger from the CCPx
module will not set the Timer1 or Timer3
interrupt flag bits.
FIGURE 15-2:
COMPARE MODE OPERATION BLOCK DIAGRAM
Special Event Trigger will:
Reset Timer1 or Timer3, but not set Timer1 or Timer3 interrupt flag bit
and set bit GO/DONE (ADCON0<2>)
which starts an A/D conversion (CCP2 only)
Set Flag bit CCP1IF
RC2/CCP1 pin
TRISC<2>
Output Enable
QS
R
Output
Logic
CCP1CON<3:0>
Mode Select
Match
CCPR1H CCPR1L
Comparator
T3CCP2
01
Special Event Trigger
TMR1H TMR1L
TMR3H TMR3L
Set Flag bit CCP2IF T3CCP1
T3CCP2
RC1/CCP2 pin
TRISC<1>
Output Enable
QS
R
Output
Logic
CCP2CON<3:0>
Mode Select
Match
01
Comparator
CCPR2H CCPR2L
 2004 Microchip Technology Inc.
DS30491C-page 171