Atmel AT90PWM2 Manual page 142

16.7.2 Modes of Operation
16.7.2.1 Normal Mode
16.7.2.2 Enhanced Mode
DT0 OT0
PSCOUTn0
PSCOUTn1
Period
4317I–AVR–01/08
The simplest mode of operation is the normal mode. See
The active time of PSCOUTn0 is given by the OT0 value. The active time of PSCOUTn1 is given
by the OT1 value. Both of them are 12 bit values. Thanks to DT0 & DT1 to ajust the dead time
between PSCOUTn0 and PSCOUTn1 active signals.
The waveform frequency is defined by the following equation:
f =
PSCn
The Enhanced Mode uses the previously described method to generate a high resolution
frequency.
Figure 16-13. Enhanced Mode, Timing Diagram
DT1 OT1
T1
The supplementary step in counting to generate f
in the frame according to the fractional divider.
lated frame," on page 142.
The waveform frequency is defined by the following equations:
f2
d is the fractionel divider factor.
f
1
----------------------------- - = ----------------------------------------------------------------------
(
PSCnCycle OT0 + OT1
DT0 OT0
SeeTable 16-5, "Distribution of fb2 in the modu-
1
f1 = ----- - = ----------------------------------------------------------------------
(
PSCn
T OT0 +
1
1
= ----- - = ------------------------------------------------------------------------------- -
(
PSCn
T OT0 + OT1
2
d
×
f = ----- - f1
AVERAGE PSCn
16
AT90PWM2/3/2B/3B
Figure 16-6.
CLK_PSCn
= =
)
+ DT0 + DT1
DT1
OT1+1
T2
is added on the PSCn0 signal while needed
b2
f
CLK_PSCn
)
OT1 + DT0 + DT1
f
CLK_PSCn
)
1
+ DT0 + DT1 +
16 d –
×
+ -------------- - f2
PSCn
16
1
DT0
143