AT90PWM2B-16SU 查看數據表（PDF） - Atmel Corporation

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AT90PWM2B-16SU

8-bit Atmel Microcontroller with 8K Bytes In-System Programmable Flash

Atmel Corporation 

AT90PWM2/3/2B/3B

16.7.2 Modes of Operation

16.7.2.1

Normal Mode

The simplest mode of operation is the normal mode. See Figure 16-6.

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 adjust the dead time

between PSCOUTn0 and PSCOUTn1 active signals.

The waveform frequency is defined by the following equation:

fPSCn=

--------------1---------------

PSCnCycle

=

---O-----T---0-----+-----O--f--C-T--L-1--K---_+---P--D-S---C-T---n-0----+-----D-----T----1----

16.7.2.2

Enhanced Mode

The Enhanced Mode uses the previously described method to generate a high resolution

frequency.

Figure 16-13. Enhanced Mode, Timing Diagram

DT0

PSCOUTn0

PSCOUTn1

Period

OT0

DT1

OT1

DT0

OT0

DT1

OT1+1

DT0

T1

T2

The supplementary step in counting to generate fb2 is added on the PSCn0 signal while needed

in the frame according to the fractional divider. See Table 16-5, “Distribution of fb2 in the modu-

lated frame,” on page 143.

The waveform frequency is defined by the following equations:

f1PSCn

=

--1---

T1

=

-----------------------f--C---L---K---_---P---S---C----n-----------------------

OT0 + OT1 + DT0 + DT1

f2PSCn

=

--1---

T2

=

----------------------------f-C----L---K---_--P----S---C---n-----------------------------

OT0 + OT1 + DT0 + DT1 + 1

fAVERAGE

=

1----6-----–----d--

16

f1PS

C

n

+

--d----

16

f2PS

C

n

d is the fractional divider factor.

4317K–AVR–03/2013

144

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