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Chapter 14 Pulse Width Modulator with Fault Protection (PMF15B6CV3)
MC9S12ZVM Family Reference Manual Rev. 1.3
524
Freescale Semiconductor
14.4.2
Prescaler
To permit lower PWM frequencies, the prescaler produces the PWM clock frequency by dividing the core
clock frequency by one, two, four, and eight. Each PWM generator has its own prescaler divisor. Each
prescaler is buffered and will not be used by its PWM generator until the corresponding Load OK bit is set
and a new PWM reload cycle begins.
14.4.3
PWM Generator
Each PWM generator contains a 15-bit up/down PWM counter producing output signals with software-
selectable
•
Alignment — The logic state of each pair EDGE bit determines whether the PWM pair outputs are
edge-aligned or center-aligned
•
Period — The value written to each pair PWM counter modulo register is used to determine the
PWM pair period. The period can also be varied by using the prescaler
•
With edge-aligned output, the modulus is the period of the PWM output in clock cycles
•
With center-aligned output, the modulus is one-half of the PWM output period in clock cycles
•
Pulse width — The number written to the PWM value register determines the pulse width duty
cycle of the PWM output in clock cycles
— With center-aligned output, the pulse width is twice the value written to the PWM value register
— With edge-aligned output, the pulse width is the value written to the PWM value register
14.4.3.1
Alignment and Compare Output Polarity
Each edge-align bit, EDGEx, selects either center-aligned or edge-aligned PWM generator outputs.
PWM compare output polarity is selected by the CINV
n
bit field in the source control (PMFCINV)
register. Please see the output operations in
and
The PWM compare output is driven to a high state when the value of PWM value (PMFVAL
n
) register is
greater than the value of PWM counter, and PWM compare is counting downwards if the corresponding
channel CINV
n
=0. Or, the PWM compare output is driven to low state if the corresponding channel
CINV
n
=1.
The PWM compare output is driven to low state when the value of PWM value (PMFVAL
n
) register
matches the value of PWM counter, and PWM counter is counting upwards if the corresponding channel
CINV
n
=0. Or, the PWM compare output is driven to high state if the corresponding channel CINV
n
=1.
Содержание MC9S12ZVM series
Страница 116: ...Chapter 2 Port Integration Module S12ZVMPIMV1 MC9S12ZVM Family Reference Manual Rev 1 3 116 Freescale Semiconductor ...
Страница 242: ...Chapter 7 ECC Generation Module SRAM_ECCV1 MC9S12ZVM Family Reference Manual Rev 1 3 242 Freescale Semiconductor ...
Страница 384: ...Chapter 10 Supply Voltage Sensor BATSV3 MC9S12ZVM Family Reference Manual Rev 1 3 384 Freescale Semiconductor ...
Страница 484: ...Chapter 13 Programmable Trigger Unit PTUV2 MC9S12ZVM Family Reference Manual Rev 1 3 484 Freescale Semiconductor ...
Страница 662: ...Chapter 17 Gate Drive Unit GDUV4 MC9S12ZVM Family Reference Manual Rev 1 3 662 Freescale Semiconductor ...
Страница 684: ...Chapter 18 LIN Physical Layer S12LINPHYV2 MC9S12ZVM Family Reference Manual Rev 1 3 684 Freescale Semiconductor ...
Страница 740: ...Chapter 19 128 KB Flash Module S12ZFTMRZ128K512V2 MC9S12ZVM Family Reference Manual Rev 1 3 740 Freescale Semiconductor ...
Страница 756: ...Appendix A MCU Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 756 Freescale Semiconductor ...
Страница 772: ...Appendix D LINPHY Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 772 Freescale Semiconductor ...
Страница 776: ...Appendix E GDU Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 776 Freescale Semiconductor ...
Страница 788: ...Appendix I MSCAN Electrical Specifications MC9S12ZVM Family Reference Manual Rev 1 3 788 Freescale Semiconductor ...
Страница 790: ...Appendix J Package Information MC9S12ZVM Family Reference Manual Rev 1 3 790 Freescale Semiconductor ...