NXP Semiconductors KE1xF Series, Reference Manual, Page: 1106 / 1483

0 1 2 3 4 5 6 7 8 9 A B C 0 1 2 3 4 5 6 7 8 9 A B C
dithering
(one unit of
FTM counter)
channel (n) output
FTM counter
accumulator 0x1B 0x1E
overflow
0x01
0 D C B A 1
channel (n) is in EPWM with high-true pulses
channel (n) ELSB:ELSA = 2'b10
CNTIN = 0x0000
MOD = 0x000C
FRACMOD = 0x03
C(n)V = 0x0009
T is the period of one unit of FTM counter
PWM period T1 =
(MOD - CNTIN + 0x0001) x T =
0x000D x T
PWM period T2 =
(MOD - CNTIN + 0x0001) x T =
0x000E x T
Figure 41-102. PWM Period Dithering with Up Counting
Assuming:
• the FTM counter is an up counter,
• T is one unit of FTM counter,
• the PWM period without period dithering is [(MOD - CNTIN + 1) x T],
• the number of PWM periods with period dithering is FRACMOD,
• the PWM period with period dithering is [(MOD - CNTIN + 1 + 1) x T],
thus, the average period (in decimal) is [(MOD - CNTIN + 1) + (FRACMOD/32)] x T,
where the integer value is (MOD - CNTIN + 1) and the fractional value is (FRACMOD/
32). See the example below.
Functional description
Kinetis KE1xF Sub-Family Reference Manual, Rev. 4, 06/2019
1106 NXP Semiconductors