PIC18F2331/2431/4331/4431
18.1 Control Registers
18.2 Module Functionality
The operation of the PWM module is controlled by a
total of 22 registers. Eight of these are used to
configure the features of the module:
The PWM module supports several modes of operation
that are beneficial for specific power and motor control
applications. Each mode of operation is described in
subsequent sections.
• PWM Timer Control Register 0 (PTCON0)
• PWM Timer Control Register 1 (PTCON1)
• PWM Control Register 0 (PWMCON0)
• PWM Control Register 1 (PWMCON1)
• Dead-Time Control Register (DTCON)
• Output Override Control Register (OVDCOND)
• Output State Register (OVDCONS)
The PWM module is composed of several functional
blocks. The operation of each is explained separately
in relation to the several modes of operation:
• PWM Time Base
• PWM Time Base Interrupts
• PWM Period
• PWM Duty Cycle
• Fault Configuration Register (FLTCONFIG)
• Dead-Time Generators
• PWM Output Overrides
• PWM Fault Inputs
There are also 14 registers that are configured as
seven register pairs of 16 bits. These are used for the
configuration values of specific features. They are:
• PWM Special Event Trigger
• PWM Time Base Registers (PTMRH and PTMRL)
• PWM Time Base Period Registers (PTPERH and
PTPERL)
18.3 PWM Time Base
• PWM Special Event Trigger Compare Registers
(SEVTCMPH and SEVTCMPL)
The PWM time base is provided by a 12-bit timer with
prescaler and postscaler functions. A simplified block
diagram of the PWM time base is shown in Figure 18-4.
The PWM time base is configured through the
PTCON0 and PTCON1 registers. The time base is
enabled or disabled by respectively setting or clearing
the PTEN bit in the PTCON1 register.
• PWM Duty Cycle #0 Registers
(PDC0H and PDC0L)
• PWM Duty Cycle #1 Registers
(PDC1H and PDC1L)
• PWM Duty Cycle #2 Registers
(PDC2H and PDC2L)
Note:
The PTMR register pair (PTMRL:PTMRH)
is not cleared when the PTEN bit is
cleared in software.
• PWM Duty Cycle #3 Registers
(PDC3H and PDC3L)
All of these register pairs are double-buffered.
DS39616D-page 176
2010 Microchip Technology Inc.
MICROCHIP [ MICROCHIP ]
