PIC18F25J11-I/PT MICROCHIP [Microchip Technology], PIC18F25J11-I/PT Datasheet - Page 245

• Manufacturer Part Number: PIC18F25J11-I/PT
• Description: 28/44-Pin, Low-Power, High-Performance Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

17.3
In Compare mode, the 16-bit CCPRx register value is
constantly compared against either the TMR1 or TMR3
register pair value. When a match occurs, the ECCPx
pin can be:
• Driven high
• Driven low
• Toggled (high-to-low or low-to-high)
• Remain unchanged (that is, reflects the state of
The action on the pin is based on the value of the mode
select bits (CCPxM<3:0>). At the same time, the
interrupt flag bit, CCPxIF, is set.
17.3.1
Users must configure the ECCPx pin as an output by
clearing the appropriate TRIS bit.
FIGURE 17-2:
© 2009 Microchip Technology Inc.
the I/O latch)
Note:
Compare Mode
ECCP PIN CONFIGURATION
Clearing the CCPxCON register will force
the ECCPx compare output latch (depend-
ing on device configuration) to the default
low level. This is not the PORTx I/O data
latch.
0
1
T3CCP1
COMPARE MODE OPERATION BLOCK DIAGRAM
CCPR1H
TMR1H
TMR3H
Comparator
CCPR1L
TMR1L
TMR3L
Compare
Match
Set CCP1IF
(Timer1/Timer3 Reset, A/D Trigger)
PIC18F46J11 FAMILY
17.3.2
Timer1 and/or Timer3 must be running in Timer mode
or Synchronized Counter mode if the ECCP module is
using the compare feature. In Asynchronous Counter
mode, the compare operation will not work reliably.
17.3.3
When the Generate Software Interrupt mode is chosen
(CCPxM<3:0> = 1010), the ECCPx pin is not affected;
only the CCPxIF interrupt flag is affected.
17.3.4
The ECCP module is equipped with a Special Event
Trigger. This is an internal hardware signal generated
in Compare mode to trigger actions by other modules.
The Special Event Trigger is enabled by selecting
the
(CCPxM<3:0> = 1011).
The Special Event Trigger resets the Timer register pair
for whichever timer resource is currently assigned as the
module’s time base. This allows the CCPRx registers to
serve as a programmable period register for either timer.
The Special Event Trigger can also start an A/D conver-
sion. In order to do this, the A/D converter must already
be enabled.
Special Event Trigger
CCP1CON<3:0>
Compare
Output
Logic
4
TIMER1/TIMER3 MODE SELECTION
SOFTWARE INTERRUPT MODE
SPECIAL EVENT TRIGGER
Special
S
R
Q
Output Enable
Event
TRIS
DS39932C-page 245
ECCP1 Pin
Trigger
mode