s908ab32ag0cfue Freescale Semiconductor, Inc, s908ab32ag0cfue Datasheet - Page 177

• Manufacturer Part Number: s908ab32ag0cfue
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

11.5.4 Pulse Width Modulation (PWM)
MC68HC908AB32
Freescale Semiconductor
—
Rev. 1.1
By using the toggle-on-overflow feature with an output compare channel,
the TIMA can generate a PWM signal. The value in the TIMA counter
modulo registers determines the period of the PWM signal. The channel
pin toggles when the counter reaches the value in the TIMA 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
TIMA to clear the channel pin on output compare if the state of the PWM
pulse is logic one. Program the TIMA to set the pin if the state of the
PWM pulse is logic zero.
The value in the TIMA 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 TIMA 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 TIMA 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 TIMA channel registers
produces a duty cycle of 128/256 or 50%.
Figure 11-3
TACHx
OVERFLOW
Timer Interface Module A (TIMA)
Figure 11-3PWM Period and Pulse Width
shows, the output compare value in the TIMA channel
PULSE
WIDTH
11.10.1 TIMA Status and Control
PERIOD
COMPARE
OUTPUT
OVERFLOW
COMPARE
Timer Interface Module A (TIMA)
OUTPUT
OVERFLOW
Register.
Technical Data
COMPARE
OUTPUT
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