AT90PWM216_14 Datasheet, PDF (135/344 Pages) ATMEL Corporation – Atmel 8-bit Microcontroller with 16K Bytes In-System Programmable Flash

The waveform frequency is defined by the following equation:
f_PSCn= _P-----_S---_C----_n--¹--_C----_y---_c---_l--_e- = _---_O-----_T---₀-----+-----_O--^f--^C-_T--^L-₁--^K---^__+---^P--_D-^S---^C-_T---ⁿ-₀----+-----_D-----_T----₁---_-
15.7.2.2 Enhanced Mode
The Enhanced Mode uses the previously described method to generate a high resolution frequency.
Figure 15-13. Enhanced Mode, Timing Diagram
DT0
OT0
PSCOUTn0
DT1
OT1
DT0
OT0
DT1
OT1+1
DT0
PSCOUTn1
Period
T1
T2
The supplementary step in counting to generate f_b2 is added on the PSCn0 signal while needed in the frame
according to the fractional divider. SeeTable 15-5, “Distribution of fb2 in the modulated frame,” on page 134.
The waveform frequency is defined by the following equations:
f1_PSCn
=
--¹---
T₁
=
^---O^-----T^---0^-----+-----O^--f--C-T^--L-1^--K---_+---^P--D^-S---C-T^---n-0^----+-----D^-----T^----1^---^-
f2_PSCn = _T--¹--₂- = _---_O-----_T---₀-----+-----_O-----_T--^f-₁^C----^L-+--^K---^__D--^P---_T-^S---₀^C---ⁿ-+-----_D-----_T----₁----+-----₁----_-
f_AVERAGE = ^---¹---⁶-₁----₆^–-----d---^  f1_PSCn + ₁--^d--₆--  f2_PSCn
d is the fractional divider factor.
15.8
PSC Inputs
Each part A or B of PSC has its own system to take into account one PSC input. According to PSC n Input A/B
Control Register (see description 15.25.14page 159), PSCnIN0/1 input can act has a Retrigger or Fault input.
This system A or B is also configured by this PSC n Input A/B Control Register (PFRCnA/B).
AT90PWM216/316 [DATASHEET] 135
7710H–AVR–07/2013