PIC18F2480/2580/4480/4580
In addition to the expanded range of modes available
17.2 Capture and Compare Modes
through the CCP1CON register, the ECCP module has
two additional registers associated with Enhanced
PWM operation and auto-shutdown features. They are:
Except for the operation of the Special Event Trigger
discussed below, the Capture and Compare modes of
the ECCP1 module are identical in operation to that of
CCP1. These are discussed in detail in Section 16.2
“Capture Mode” and Section 16.3 “Compare
Mode”.
• ECCP1DEL (Dead-Band Delay)
• ECCP1AS (Auto-Shutdown Control)
17.1 ECCP Outputs and Configuration
17.2.1
SPECIAL EVENT TRIGGER
The Enhanced CCP module may have up to four PWM
outputs, depending on the selected operating mode.
These outputs, designated P1A through P1D, are
multiplexed with I/O pins on PORTC and PORTD. The
outputs that are active depend on the CCP operating
mode selected. The pin assignments are summarized
in Table 17-1.
The Special Event Trigger output of ECCP1 resets the
TMR1 or TMR3 register pair, depending on which timer
resource is currently selected. This allows the ECCP1
register to effectively be a 16-bit programmable period
register for Timer1 or Timer3. The Special Event
Trigger for ECCP1 can also start an A/D conversion. In
order to start the conversion, the A/D Converter must
be previously enabled.
To configure the I/O pins as PWM outputs, the proper
PWM mode must be selected by setting the
EPWM1M<1:0> and CCP1M<3:0> bits. The appropriate
TRISC and TRISD direction bits for the port pins must
also be set as outputs.
17.3 Standard PWM Mode
When configured in Single Output mode, the ECCP
module functions identically to the standard CCP
module in PWM mode, as described in Section 16.4
“PWM Mode”. This is also sometimes referred to as
“Compatible CCP” mode, as in Table 17-1.
17.1.1
ECCP MODULES AND TIMER
RESOURCES
Like the standard CCP modules, the ECCP module can
utilize Timers 1, 2 or 3, depending on the mode
selected. Timer1 and Timer3 are available for modules
in Capture or Compare modes, while Timer2 is
available for modules in PWM mode. Interactions
between the standard and Enhanced CCP modules are
identical to those described for standard CCP modules.
Additional details on timer resources are provided in
Note:
When setting up single output PWM opera-
tions, users are free to use either of the
processes described in Section 16.4.4
“Setup for PWM Operation” or
Section 17.4.9 “Setup for PWM Opera-
tion”. The latter is more generic, but will
work for either single or multi-output PWM.
Section 16.1.1
“CCP
Modules
and
Timer
Resources”.
TABLE 17-1: PIN ASSIGNMENTS FOR VARIOUS ECCP MODES
CCP1CON
ECCP Mode
RD4
RD5
RD6
RD7
Configuration
All PIC18F4480/4580 Devices:
Compatible CCP
Dual PWM
00xx 11xx
10xx 11xx
x1xx 11xx
CCP1
P1A
RD5/PSP5
RD6/PSP6
RD6/PSP6
P1C
RD7/PSP7
RD7/PSP7
P1D
P1B
P1B
Quad PWM
P1A
Legend: x= Don’t care. Shaded cells indicate pin assignments not used by ECCP1 in a given mode.
DS39637D-page 178
© 2009 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
