PIC16F818/819
9.0
CAPTURE/COMPARE/PWM
(CCP) MODULE
The CCP module’s input/output pin (CCP1) can be
configured as RB2 or RB3. This selection is set in bit 12
(CCPMX) of the Configuration Word register.
Additional information on the CCP module is available
in the
“PICmicro
®
Mid-Range MCU Family Reference
Manual”
(DS33023) and in Application Note
AN594,
“Using
the CCP Module(s)”
(DS00594).
The Capture/Compare/PWM (CCP) module contains a
16-bit register that can operate as a:
• 16-bit Capture register
• 16-bit Compare register
• PWM Master/Slave Duty Cycle register
module modes.
Capture/Compare/PWM Register 1 (CCPR1) is com-
prised of two 8-bit registers: CCPR1L (low byte) and
CCPR1H (high byte). The CCP1CON register controls
the operation of CCP1. The special event trigger is
generated by a compare match which will reset Timer1
and start an A/D conversion (if the A/D module is
enabled).
TABLE 9-1:
CCP MODE – TIMER
RESOURCE
Timer Resource
Timer1
Timer1
Timer2
CCP Mode
Capture
Compare
PWM
REGISTER 9-1:
CCP1CON: CAPTURE/COMPARE/PWM CONTROL REGISTER 1 (ADDRESS 17h)
U-0
—
bit 7
U-0
—
R/W-0
CCP1X
R/W-0
CCP1Y
R/W-0
CCP1M3
R/W-0
CCP1M2
R/W-0
CCP1M1
R/W-0
CCP1M0
bit 0
bit 7-6
bit 5-4
Unimplemented:
Read as ‘0’
CCP1X:CCP1Y:
PWM Least Significant bits
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPRxL.
CCP1M3:CCP1M0:
CCP1 Mode Select bits
0000
= Capture/Compare/PWM disabled (resets CCP1 module)
0100
= Capture mode, every falling edge
0101
= Capture mode, every rising edge
0110
= Capture mode, every 4th rising edge
0111
= Capture mode, every 16th rising edge
1000
= Compare mode, set output on match (CCP1IF bit is set)
1001
= Compare mode, clear output on match (CCP1IF bit is set)
1010
= Compare mode, generate software interrupt on match (CCP1IF bit is set, CCP1 pin is
unaffected)
1011
= Compare mode, trigger special event (CCP1IF bit is set, CCP1 pin is unaffected);
CCP1 resets TMR1 and starts an A/D conversion (if A/D module is enabled)
11xx
= PWM mode
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 3-0
2004 Microchip Technology Inc.
DS39598E-page 65
MICROCHIP [ MICROCHIP TECHNOLOGY ]
