mc9s12xf512 Freescale Semiconductor, Inc, mc9s12xf512 Datasheet - Page 944

• Manufacturer Part Number: mc9s12xf512
• Description: S12x Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

Chapter 20 Pulse Width Modulator with Fault Protection (PMF15B6C) Module
20.4.5.4
Output polarity of the PWMs is determined by two options: TOPNEG and BOTNEG. The top polarity
option, TOPNEG, controls the polarity of PWM0, PWM2 and PWM4. The bottom polarity option,
BOTNEG, controls the polarity of PWM1, PWM3 and PWM5. Positive polarity means when the PWM is
active its output is high. Conversely, negative polarity means when the PWM is active its output is low.
The TOPNEG and BOTNEG are in the configure register. TOPNEG is the output of PWM0, PWM2 and
PWM4. They are active low. If TOPNEG is set, PWM0, PWM2, and PWM4 outputs become active-low.
When BOTNEG is set, PWM1, PWM3, and PWM5 outputs are active-low. When these bits are clear, their
respective PWM pins are active-high. See
20.4.6
Setting output control enable bit, OUTCTLx, enables software to drive the PWM outputs rather than the
PWM generator. In an independent mode, with OUTCTLx = 1, the output bit OUTx, controls the PWMx
944
Software Output Control
NEGATIVE POLARITY
POSITIVE POLARITY
Output Polarity
CENTER-ALIGNED
CENTER-ALIGNED
DESIRED LOAD VOLTAGE
UP/DOWN COUNTER
UP/DOWN COUNTER
MODULUS = 4
MODULUS = 4
LOAD VOLTAGE
BOTTOM PWM
Figure 20-60. Correction with Negative Current
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
MC9S12XF - Family Reference Manual, Rev.1.19
TOP PWM
Figure 20-61. PWM Polarity
Figure 20-59
and
NEGATIVE POLARITY
POSITIVE POLARITY
Figure
EDGE-ALIGNED
EDGE-ALIGNED
20-60.
MODULUS = 4
UP COUNTER
MODULUS = 4
UP COUNTER
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
Freescale Semiconductor