PIC16LF1454 Datasheet, PDF (289/418 Pages) Microchip Technology – 14/20-Pin Flash, 8-Bit USB Microcontrollers with XLP Technology

PIC16(L)F1454/5/9
24.1.5 PWM RESOLUTION
The resolution determines the number of available duty
cycles for a given period. For example, a 10-bit resolu-
tion will result in 1024 discrete duty cycles, whereas an
8-bit resolution will result in 256 discrete duty cycles.
The maximum PWM resolution is 10 bits when PR2 is
255. The resolution is a function of the PR2 register
value as shown by Equation 24-4.
EQUATION 24-4: PWM RESOLUTION
Resolution = ^{l--o---g----}--4---l-^_{o--P-g---R-}--2-2---_--+-----1----^--^ bits
Note:
If the pulse width value is greater than the
period, the assigned PWM pin(s) will
remain unchanged.
TABLE 24-1: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)
PWM Frequency
0.31 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz
Timer Prescale (1, 4, 64)
PR2 Value
Maximum Resolution (bits)
64
0xFF
10
4
0xFF
10
1
0xFF
10
1
0x3F
8
1
0x1F
7
208.3 kHz
1
0x17
6.6
TABLE 24-2: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 8 MHz)
PWM Frequency
0.31 kHz 4.90 kHz 19.61 kHz 76.92 kHz 153.85 kHz
Timer Prescale (1, 4, 64)
PR2 Value
Maximum Resolution (bits)
64
0x65
8
4
0x65
8
1
0x65
8
1
0x19
6
1
0x0C
5
200.0 kHz
1
0x09
5
24.1.6 OPERATION IN SLEEP MODE
In Sleep mode, the TMR2 register will not increment
and the state of the module will not change. If the
PWMx pin is driving a value, it will continue to drive that
value. When the device wakes up, TMR2 will continue
from its previous state.
24.1.7 CHANGES IN SYSTEM CLOCK
FREQUENCY
The PWM frequency is derived from the system clock
frequency (FOSC). Any changes in the system clock fre-
quency will result in changes to the PWM frequency.
Refer to Section 6.0 “Active Clock Tuning (ACT)
Module” for additional details.
24.1.8 EFFECTS OF RESET
Any Reset will force all ports to Input mode and the
PWM registers to their Reset states.
 2012 Microchip Technology Inc.
Preliminary
DS41639A-page 289