mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 366

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

Chapter 11 Pulse Width Modulator with Fault Protection (PMF15B6CV2)
11.4.6
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
channel. In a complementary channel operation the even OUTCTL bit is used to enable software output
control for the pair. But the OUTCTL bits must be switched in pairs for proper operation. The OUTCTLx
and OUTx bits are in the PWM output control register.
In independent PWM operation, setting or clearing the OUTx bit activates or deactivates the PWMx
output.
In complementary channel operation, the even-numbered OUTx bits replace the PWM generator outputs
as inputs to the deadtime generators. Complementary channel pairs still cannot be active simultaneously,
and the deadtime generators continue to insert deadtime in both channels of that pair, whenever an even
OUTx bit toggles. Even OUTx bits control the top PWM signals while the odd OUTx bits control the
bottom PWM signals with respect to the even OUTx bits. Setting the odd OUTx bit makes its
corresponding PWMx the complement of its even pair, while clearing the odd OUTx bit deactivates the
odd PWMx.
366
Software Output Control
NEGATIVE POLARITY
POSITIVE POLARITY
CENTER-ALIGNED
CENTER-ALIGNED
During software output control, TOPNEG and BOTNEG still control output
polarity. It will take upto 3 clock cycles to see the effect of output control on
the PWM output pins.
UP/DOWN COUNTER
UP/DOWN COUNTER
MODULUS = 4
MODULUS = 4
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
PWM = 0
PWM = 1
PWM = 2
PWM = 3
PWM = 4
MC9S12E256 Data Sheet, Rev. 1.08
Figure 11-61. PWM Polarity
NOTE
NEGATIVE POLARITY
POSITIVE POLARITY
EDGE-ALIGNED
EDGE-ALIGNED
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
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