PIC18F25K80 MICROCHIP [Microchip Technology], PIC18F25K80 Datasheet - Page 275

• Manufacturer Part Number: PIC18F25K80
• Manufacturer: MICROCHIP [Microchip Technology]

20.2.2
The timers that are to be used with the capture feature
(Timer1 2, 3 or 4) must be running in Timer mode or
Synchronized
Counter mode, the capture operation may not work.
The timer to be used with each ECCP module is
selected in the CCPTMRS register
20.2.3
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep the
CCP1IE interrupt enable bit clear to avoid false inter-
rupts. The interrupt flag bit, CCP1IF, should also be
cleared following any such change in operating mode.
FIGURE 20-1:
 2011 Microchip Technology Inc.
ECCP1 Pin
TIMER1/2/3/4 MODE SELECTION
SOFTWARE INTERRUPT
Counter
CCP1CON<3:0>
Prescaler
 1, 4, 16
CAPTURE MODE OPERATION BLOCK DIAGRAM
mode.
Q1:Q4
4
(Register
In
Edge Detect
4
and
Asynchronous
20-2).
Set CCP1IF
Preliminary
C1TSEL0
C1TSEL1
C1TSEL2
C1TSEL0
C1TSEL1
C1TSEL2
PIC18F66K80 FAMILY
20.2.4
There are four prescaler settings in Capture mode; they
are specified as part of the operating mode selected by
the mode select bits (CCP1M<3:0>). Whenever the
ECCP module is turned off, or Capture mode is dis-
abled, the prescaler counter is cleared. This means
that any Reset will clear the prescaler counter.
Switching from one capture prescaler to another may
generate an interrupt. Also, the prescaler counter will
not be cleared; therefore, the first capture may be from
a non-zero prescaler.
recommended method for switching between capture
prescalers. This example also clears the prescaler
counter and will not generate the “false” interrupt.
EXAMPLE 20-1:
CLRF
MOVLW
MOVWF
CCP1CON
NEW_CAPT_PS ; Load WREG with the
CCP1CON
ECCP PRESCALER
CHANGING BETWEEN
CAPTURE PRESCALERS
; Turn ECCP module off
; new prescaler mode
; value and ECCP ON
; Load ECCP1CON with
; this value
Example 20-1
TMR3
Enable
TMR1
Enable
CCPR1H
TMR3H
TMR1H
DS39977C-page 275
CCPR1L
TMR1L
TMR3L
provides the