MC68HC908AZ32ACFU MOTOROLA [Motorola, Inc], MC68HC908AZ32ACFU Datasheet - Page 318

• Manufacturer Part Number: MC68HC908AZ32ACFU
• Description: Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Timer Interface Module B (TIMB)
19.4.4 Pulse Width Modulation (PWM)
Advance Information
318
By using the toggle-on-overflow feature with an output compare channel,
the TIMB can generate a PWM signal. The value in the TIMB counter
modulo registers determines the period of the PWM signal. The channel
pin toggles when the counter reaches the value in the TIMB counter
modulo registers. The time between overflows is the period of the PWM
signal.
As
registers determines the pulse width of the PWM signal. The time
between overflow and output compare is the pulse width. Program the
TIMB to clear the channel pin on output compare if the state of the PWM
pulse is logic 1. Program the TIMB to set the pin if the state of the PWM
pulse is logic 0.
The value in the TIMB counter modulo registers and the selected
prescaler output determines the frequency of the PWM output. The
frequency of an 8-bit PWM signal is variable in 256 increments. Writing
$00FF (255) to the TIMB counter modulo registers produces a PWM
period of 256 times the internal bus clock period if the prescaler select
value is $000 (see
The value in the TIMB channel registers determines the pulse width of
the PWM output. The pulse width of an 8-bit PWM signal is variable in
256 increments. Writing $0080 (128) to the TIMB channel registers
produces a duty cycle of 128/256 or 50%.
PTEx/TCHx
Freescale Semiconductor, Inc.
Figure 19-3
For More Information On This Product,
OVERFLOW
Timer Interface Module B (TIMB)
Go to: www.freescale.com
Figure 19-3. PWM Period and Pulse Width
shows, the output compare value in the TIMB channel
PULSE
WIDTH
19.9.1 TIMB Status and Control
PERIOD
COMPARE
OUTPUT
OVERFLOW
COMPARE
OUTPUT
68HC908AZ32A — Rev 0.0
OVERFLOW
Register).
MOTOROLA
COMPARE
OUTPUT