PIC18F23K22 Datasheet, PDF (188/492 Pages) Microchip Technology – 28/40/44-Pin, Low-Power, High-Performance Microcontrollers with nanoWatt XLP Technology

PIC18(L)F2X/4XK22
14.4 PWM (Enhanced Mode)
The enhanced PWM function described in this section is
available for CCP modules ECCP1, ECCP2 and
ECCP3, with any differences between modules noted.
The enhanced PWM mode generates a Pulse-Width
Modulation (PWM) signal on up to four different output
pins with up to 10 bits of resolution. The period, duty
cycle, and resolution are controlled by the following
registers:
• PRx registers
• TxCON registers
• CCPRxL registers
• CCPxCON registers
The ECCP modules have the following additional PWM
registers which control Auto-shutdown, Auto-restart,
Dead-band Delay and PWM Steering modes:
• ECCPxAS registers
• PSTRxCON registers
• PWMxCON registers
The enhanced PWM module can generate the following
five PWM Output modes:
• Single PWM
• Half-Bridge PWM
• Full-Bridge PWM, Forward Mode
• Full-Bridge PWM, Reverse Mode
• Single PWM with PWM Steering Mode
To select an Enhanced PWM Output mode, the
PxM<1:0> bits of the CCPxCON register must be
configured appropriately.
The PWM outputs are multiplexed with I/O pins and are
designated PxA, PxB, PxC and PxD. The polarity of the
PWM pins is configurable and is selected by setting the
CCPxM bits in the CCPxCON register appropriately.
Figure 14-5 shows an example of a simplified block
diagram of the Enhanced PWM module.
Table 14-12 shows the pin assignments for various
Enhanced PWM modes.
Note 1: The corresponding TRIS bit must be
cleared to enable the PWM output on the
CCPx pin.
2: Clearing the CCPxCON register will
relinquish control of the CCPx pin.
3: Any pin not used in the enhanced PWM
mode is available for alternate pin
functions, if applicable.
4: To prevent the generation of an
incomplete waveform when the PWM is
first enabled, the ECCP module waits
until the start of a new PWM period before
generating a PWM signal.
FIGURE 14-5:
EXAMPLE SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODE
Duty Cycle Registers
CCPRxL
DCxB<1:0>
CCPRxH (Slave)
Comparator
R
TMRx
(1)
S
Comparator
PRx
Clear Timer,
toggle PWM pin and
latch duty cycle
PxM<1:0>
CCPxM<3:0>
2
4
CCPx/PxA
TRISx
PxB
Q
Output
Controller
TRISx
PxC
TRISx
PxD
PWMxCON
TRISx
CCPx/PxA
PxB
PxC⁽²⁾
PxD⁽²⁾
Note 1:
2:
The 8-bit timer TMRx register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler to create the 10-bit time
base.
PxC and PxD are not available on Half-Bridge ECCP Modules.
DS41412B-page 188
Preliminary
 2010 Microchip Technology Inc.