PIC16F882-I Datasheet, PDF (132/328 Pages) Microchip Technology – 28/40/44-Pin, Enhanced Flash-Based 8-Bit CMOS Microcontrollers

PIC16F882/883/884/886/887
11.5.3 PWM RESOLUTION
The resolution determines the number of available duty
cycles for a given period. For example, a 10-bit resolution
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 11-4.
EQUATION 11-4: 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 11-3: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz)
PWM Frequency
1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz
Timer Prescale (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
16
0xFF
10
4
0xFF
10
1
0xFF
10
1
0x3F
8
1
0x1F
7
208.3 kHz
1
0x17
6.6
TABLE 11-4: EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 8 MHz)
PWM Frequency
1.22 kHz 4.90 kHz 19.61 kHz 76.92 kHz 153.85 kHz 200.0 kHz
Timer Prescale (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
16
0x65
8
4
0x65
8
1
0x65
8
1
0x19
6
1
0x0C
5
1
0x09
5
DS41291F-page 130
© 2009 Microchip Technology Inc.