mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 355

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

In an edge-aligned operation, the PWM counter is an up counter. The PWM output resolution is one bus
clock cycle.
11.4.3.3
The signed 16-bit number written to the PMF value registers is the pulse width in PWM clock periods of
the PWM generator output.
Freescale Semiconductor
PWM period = PWM modulus
Duty Cycle
A PWM value less than or equal to zero deactivates the PWM output for the
entire PWM period. A PWM value greater than or equal to the modulus
activates the PWM output for the entire PWM period.
PWM PERIOD = 4 x PWM CLOCK PERIOD
$8000–$FFFF
$0000–$7FFF
Table 11-46. PWM Value and Underflow Conditions
PMFVALx
Figure 11-44. Edge-Aligned PWM Period
PWM CLOCK PERIOD
MC9S12E256 Data Sheet, Rev. 1.08
Duty cycle
MODULUS = 4
UP COUNTER
PWM clock period
COUNT
Condition
Underflow
Normal
=
Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
NOTE
------------------------------- -
MODULUS
PMFVAL
1
2
PWM Value Used
Value in registers
3
100
4
$0000
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