PIC16F883 Microchip Technology Inc., PIC16F883 Datasheet - Page 129

• Manufacturer Part Number: PIC16F883
• Description: 28/40/44-pin Flash-based, 8-bit Cmos Microcontrollers With Nanowatt Technology
• Manufacturer: Microchip Technology Inc.

11.4
In Compare mode, the 16-bit CCPRx register value is
constantly compared against the TMR1 register pair
value. When a match occurs, the CCPx module may:
• Toggle the CCPx output
• Set the CCPx output
• Clear the CCPx output
• Generate a Special Event Trigger
• Generate a Software Interrupt
The action on the pin is based on the value of the
CCPxM<3:0> control bits of the CCPx1CON register.
All Compare modes can generate an interrupt.
FIGURE 11-2:
11.4.1
The user must configure the CCPx pin as an output by
clearing the associated TRIS bit.
© 2007 Microchip Technology Inc.
Note:
CCPx
Pin
Special Event Trigger will:
• Clear TMR1H and TMR1L registers.
• NOT set interrupt flag bit TMR1IF of the PIR1 register.
• Set the GO/DONE bit to start the ADC conversion.
Output Enable
TRIS
Compare Mode
CCP PIN CONFIGURATION
Clearing the CCP1CON register will force
the CCPx compare output latch to the
default low level. This is not the PORT I/O
data latch.
Q
Special Event Trigger
CCPxCON<3:0>
R
S
Mode Select
Output
COMPARE MODE
OPERATION BLOCK
DIAGRAM
Logic
Set CCPxIF Interrupt Flag
4
(PIRx)
Match
CCPRxH CCPRxL
TMR1H
Comparator
TMR1L
PIC16F882/883/884/886/887
Preliminary
11.4.2
In Compare mode, Timer1 must be running in either
Timer mode or Synchronized Counter mode. The
compare operation may not work in Asynchronous
Counter mode.
11.4.3
When Generate Software Interrupt mode is chosen
(CCPxM<3:0> = 1010), the CCPx module does not
assert control of the CCPx pin (see the CCP1CON
register).
11.4.4
When Special Event Trigger mode is chosen
(CCPxM<3:0> = 1011), the CCPx module does the
following:
• Resets Timer1
• Starts an ADC conversion if ADC is enabled
The CCPx module does not assert control of the CCPx
pin in this mode (see the CCPxCON register).
The Special Event Trigger output of the CCP occurs
immediately upon a match between the TMR1H,
TMR1L register pair and the CCPRxH, CCPRxL
register pair. The TMR1H, TMR1L register pair is not
reset until the next rising edge of the Timer1 clock. This
allows the CCPRxH, CCPRxL register pair to
effectively provide a 16-bit programmable period
register for Timer1.
Note 1: The Special Event Trigger from the CCP
2: Removing
TIMER1 MODE SELECTION
SOFTWARE INTERRUPT MODE
SPECIAL EVENT TRIGGER
module does not set interrupt flag bit
TMRxIF of the PIR1 register.
changing the contents of the CCPRxH
and CCPRxL register pair, between the
clock edge that generates the Special
Event Trigger and the clock edge that
generates the Timer1 Reset, will preclude
the Reset from occurring.
the
match
DS41291D-page 127
condition
by