PIC18F2220/2320/4220/4320
The ECCP module differs from the CCP with the addi-
tion of an enhanced PWM mode which allows for 2 or
4 output channels, user-selectable polarity, dead band
control and automatic shutdown and restart. These
features are discussed in detail in Section 16.4
16.0 ENHANCED CAPTURE/
COMPARE/PWM (ECCP)
MODULE
Note:
The ECCP (Enhanced Capture/ Compare/
“Enhanced PWM Mode”.
PWM) module is only available on
PIC18F4X20 devices.
The control register for CCP1 is shown in Register 16-1.
It differs from the CCP1CON register of PIC18F2X20
devices in that the two Most Significant bits are
implemented to control enhanced PWM functionality.
In 40 and 44-pin devices, the CCP1 module is
implemented as standard CCP module with
a
enhanced PWM capabilities. Operation of the Capture,
Compare and standard single output PWM modes is
described in Section 15.0 “Capture/Compare/PWM
(CCP) Modules”. Discussion in that section relating to
PWM frequency and duty cycle also apply to the
enhanced PWM mode.
REGISTER 16-1: CCP1CON REGISTER FOR ENHANCED CCP OPERATION (PIC18F4X20 ONLY)
R/W-0
P1M1
R/W-0
P1M0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
DC1B1
DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0
bit 0
bit 7
bit 7-6
P1M1:P1M0: PWM Output Configuration bits
If CCP1M<3:2> = 00, 01, 10(Capture, Compare, or disabled):
xx=P1A assigned as Capture/Compare input; P1B, P1C, P1D assigned as port pins
If CCP1M<3:2> = 11(PWM modes):
00=Single output; P1A modulated; P1B, P1C, P1D assigned as port pins
01=Full-bridge output forward; P1D modulated; P1A active; P1B, P1C inactive
10= Half-bridge output; P1A, P1B modulated with dead band control; P1C, P1D assigned as port pins
11=Full-bridge output reverse; P1B modulated; P1C active; P1A, P1D inactive
bit 5-4
DC1B1:DC1B0: PWM Duty Cycle 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 CCPR1L.
bit 3-0
CCP1M3:CCP1M0: ECCP1 Mode Select bits
0000= Capture/Compare/PWM off (resets ECCP module)
0001= Unused (reserved)
0010= Compare mode, toggle output on match (ECCP1IF bit is set)
0011= Unused (reserved)
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 (ECCP1IF bit is set)
1001= Compare mode, clear output on match (ECCP1IF bit is set)
1010= Compare mode, generate software interrupt on match (ECCP1IF bit is set, ECCP1 pin
operates as a port pin for input and output)
1011= Compare mode, trigger special event (ECCP1IF bit is set, ECCP resets TMR1or TMR2
and starts an A/D conversion if the A/D module is enabled)
1100= PWM mode, P1A, P1C active-high, P1B, P1D active-high
1101= PWM mode, P1A, P1C active-high, P1B, P1D active-low
1110= PWM mode, P1A, P1C active-low, P1B, P1D active-high
1111= PWM mode, P1A, P1C active-low, P1B, P1D active-low
Legend:
R = Readable bit
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
- n = Value at POR
2003 Microchip Technology Inc.
DS39599C-page 141
MICROCHIP [ MICROCHIP ]
