PIC18F258 Datasheet, PDF (123/384 Pages) Microchip Technology – High Performance, 28/40-Pin Enhanced FLASH Microcontrollers with CAN

PIC18FXX8
15.0 CAPTURE/COMPARE/PWM
(CCP) MODULES
The CCP (Capture/Compare/PWM) module contains a
16-bit register that can operate as a 16-bit capture reg-
ister, as a 16-bit compare register, or as a PWM Duty
Cycle register.
The operation of the CCP module is identical to that of
the ECCP module (discussed in detail in Section 16.0),
with two exceptions. The CCP module has a Capture
special event trigger that can be used as a message
received time stamp for the CAN module (refer to
Section 19.0, CAN Module for CAN operation), which
the ECCP module does not. The ECCP module, on the
other hand, has enhanced PWM functionality and auto
shutdown capability. Aside from these, the operation of
the module described in the this section is the same as
the ECCP .
The control register for the CCP module is shown in
Register 15-1. Table 15-2 (following page) details the
interactions of the CCP and ECCP modules.
REGISTER 15-1: CCP1CON REGISTER
U-0
—
bit 7
U-0
R/W-0
—
DC1B1
R/W-0
DC1B0
R/W-0
CCP1M3
R/W-0
CCP1M2
R/W-0
CCP1M1
R/W-0
CCP1M0
bit 0
bit 7-6
bit 5-4
bit 3-0
Unimplemented: Read as '0'
DCxB1:DCxB0: PWM Duty Cycle bit1 and bit0
Capture mode:
Unused
Compare mode:
Unused
PWM mode:
These bits are the two LSbs (bit1 and bit0) of the 10-bit PWM duty cycle. The upper eight bits
(DCx9:DCx2) of the duty cycle are found in CCPRxL.
CCPxM3:CCPxM0: CCPx Mode Select bits
0000 = Capture/Compare/PWM off (resets CCPx module)
0001 = Reserved
0010 = Compare mode, toggle output on match (CCPxIF bit is set)
0011 = Capture mode, CAN message received (CCP1 only)
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, initialize CCP pin Low, on compare match force CCP pin High
(CCPIF bit is set)
1001 = Compare mode, initialize CCP pin High, on compare match force CCP pin Low
(CCPIF bit is set)
1010 = Compare mode, CCP pin is unaffected
(CCPIF bit is set)
1011 = Compare mode, trigger special event (CCP1IF bit is set; CCP resets TMR1 or TMR3
and starts an A/D conversion, if the 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
 2002 Microchip Technology Inc.
Preliminary
DS41159B-page 121