LM3S6610 Luminary Micro, Inc, LM3S6610 Datasheet - Page 439

• Manufacturer Part Number: LM3S6610
• Description: Lm3s6610 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

17
17.1
July 25, 2008
Pulse Width Modulator (PWM)
Pulse width modulation (PWM) is a powerful technique for digitally encoding analog signal levels.
High-resolution counters are used to generate a square wave, and the duty cycle of the square
wave is modulated to encode an analog signal. Typical applications include switching power supplies
and motor control.
The Stellaris
generator block contains one timer (16-bit down or up/down counter), two PWM comparators, a
PWM signal generator, a dead-band generator, and an interrupt selector. The control block determines
the polarity of the PWM signals, and which signals are passed through to the pins.
Each PWM generator block produces two PWM signals that can either be independent signals
(other than being based on the same timer and therefore having the same frequency) or a single
pair of complementary signals with dead-band delays inserted. The output of the PWM generation
blocks are managed by the output control block before being passed to the device pins.
The Stellaris
such as those required by a simple charge pump. It can also generate paired PWM signals with
dead-band delays, such as those required by a half-H bridge driver.
Block Diagram
Figure 17-1 on page 439 provides the Stellaris
440 provides a more detailed diagram of a Stellaris
contains two generator blocks (PWM0 and PWM1) and generates four independent PWM signals
or two paired PWM signals with dead-band delays inserted.
Figure 17-1. PWM Unit Diagram
PWM Clock
Fault
System Clock
Interrupts
Triggers
®
®
PWM module consists of two PWM generator blocks and a control block. Each PWM
PWM module provides a great deal of flexibility. It can generate simple PWM signals,
Control and
PWMSTATUS
PWMENABLE
PWMINVERT
PWMFAULT
PWMINTEN
PWMSYNC
Interrupt
PWMCTL
PWMRIS
PWMISC
Output
Status
Preliminary
®
PWM module unit diagram and Figure 17-2 on page
Generator 0
Generator 1
®
PWM generator. The LM3S6610 controller
PWM
PWM
PWM0_A
PWM0_B
PWM0_Fault
PWM1_A
PWM1_B
PWM1_Fault
LM3S6610 Microcontroller
Control
Output
PWM
Logic
PWM 0
PWM 1
PWM 2
PWM 3
439