LM3S1133 Luminary Micro, Inc, LM3S1133 Datasheet - Page 424

• Manufacturer Part Number: LM3S1133
• Description: Lm3s1133 Arm Microcontroller
• Manufacturer: Luminary Micro, Inc

Pulse Width Modulator (PWM)
17
17.1
424
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/ADC-trigger selector. The control
block determines the polarity of the PWM signals, and which signals are passed through to the pins.
The 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 block
is 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 424 provides the Stellaris
425 provides a more detailed diagram of a Stellaris
contains one generator block (PWM0) and generates two independent PWM signals or one paired
PWM signal with dead-band delays inserted.
Figure 17-1. PWM Unit Diagram
PWM Clock
Fault
System Clock
Interrupts
Triggers
®
®
PWM module provides a great deal of flexibility. It can generate simple PWM signals,
PWM module consists of one PWM generator block and a control block. The PWM
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
®
PWM generator. The LM3S1133 controller
PWM
PWM0_A
PWM0_B
PWM0_Fault
Control
Output
PWM
Logic
July 26, 2008
PWM 0
PWM 1