24.4.6 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 T2PR is 0xFF. The resolution is a function of the T2PR register value, as shown below.

Equation 24-4. PWM Resolution

Re s o l u t i o n = \frac{\log [4 (T 2 P R + 1)]}{\log (2)} b i t s

Important: If the pulse-width value is greater than the period, the assigned PWM pin(s) will remain unchanged.

Table 24-2. Example PWM Frequencies and Resolutions (F_OSC = 20 MHz)
PWM Frequency	1.22 kHz	4.88 kHz	19.53 kHz	78.12 kHz	156.3 kHz	208.3 kHz
Timer Prescale	16	4	1	1	1	1
T2PR Value	`0xFF`	`0xFF`	`0xFF`	`0x3F`	`0x1F`	`0x17`
Maximum Resolution (bits)	10	10	10	8	7	6.6

Table 24-3. Example PWM Frequencies and Resolutions (F_OSC = 8 MHz)
PWM Frequency	1.22 kHz	4.90 kHz	19.61 kHz	76.92 kHz	153.85 kHz	200.0 kHz
Timer Prescale	16	4	1	1	1	1
T2PR Value	`0x65`	`0x65`	`0x65`	`0x19`	`0x0C`	`0x09`
Maximum Resolution (bits)	8	8	8	6	5	5