Chapter 9 Pulse-Width Modulator (S12PWM8B8CV2)
S12ZVHY/S12ZVHL Family Reference Manual Rev. 1.05
338
Freescale Semiconductor
•
The counter is written (counter resets to $00)
•
The channel is disabled
In this way, the output of the PWM will always be either the old waveform or the new waveform, not some
variation in between. If the channel is not enabled, then writes to the period register will go directly to the
latches as well as the buffer.
NOTE
Reads of this register return the most recent value written. Reads do not
necessarily return the value of the currently active period due to the double
buffering scheme.
Section 9.4.2.3, “PWM Period and Duty”
for more information.
To calculate the output period, take the selected clock source period for the channel of interest (A, B, SA,
or SB) and multiply it by the value in the period register for that channel:
•
Left aligned output (CAEx = 0)
PWMx Period = Channel Clock Period * PWMPERx
•
Center Aligned Output (CAEx = 1)
PWMx Period = Channel Clock Period * (2 * PWMPERx)
For boundary case programming values, please refer to
Section 9.4.2.8, “PWM Boundary Cases”
.
1
This register is available only when the corresponding channel exists and is reserved if that channel does not exist. Writes to
a reserved register have no functional effect. Reads from a reserved register return zeroes.
Read: Anytime
Write: Anytime
9.3.2.12
PWM Channel Duty Registers (PWMDTYx)
There is a dedicated duty register for each channel. The value in this register determines the duty of the
associated PWM channel. The duty value is compared to the counter and if it is equal to the counter value
a match occurs and the output changes state.
The duty registers for each channel are double buffered so that if they change while the channel is enabled,
the change will NOT take effect until one of the following occurs:
•
The effective period ends
•
The counter is written (counter resets to $00)
Module Base + 0x0014 = PWMPER0, 0x0015 = PWMPER1, 0x0016 = PWMPER2, 0x0017 = PWMPER3
Module Base + 0x0018 = PWMPER4, 0x0019 = PWMPER5, 0x001A = PWMPER6, 0x001B = PWMPER7
7
6
5
4
3
2
1
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
Reset
1
1
1
1
1
1
1
1
Figure 9-13. PWM Channel Period Registers (PWMPERx)
Содержание MC9S12ZVHL32
Страница 21: ...S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 Freescale Semiconductor 21 PAGE INTENTIONALLY LEFT BLANK...
Страница 22: ...S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 22 Freescale Semiconductor PAGE INTENTIONALLY LEFT BLANK...
Страница 686: ...Chapter 20 ECC Generation module SRAM_ECCV1 S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 686 Freescale Semiconductor...
Страница 752: ...Chapter 22 Supply Voltage Sensor BATSV2 S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 752 Freescale Semiconductor...
Страница 774: ...Chapter 23 LIN Physical Layer S12LINPHYV2 S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 774 Freescale Semiconductor...
Страница 788: ...Appendix A MCU Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 788 Freescale Semiconductor...
Страница 794: ...Appendix B ADC Electricals S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 794 Freescale Semiconductor...
Страница 798: ...Appendix D IRC Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 798 Freescale Semiconductor...
Страница 802: ...Appendix F MSCAN Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 802 Freescale Semiconductor...
Страница 806: ...Appendix G NVM Electrical Parameters S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 806 Freescale Semiconductor...
Страница 810: ...Appendix H BATS Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 810 Freescale Semiconductor...
Страница 816: ...Appendix K OSC32K Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 816 Freescale Semiconductor...
Страница 822: ...Appendix L SPI Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 822 Freescale Semiconductor...
Страница 826: ...Appendix M LINPHY Electrical Specifications S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 826 Freescale Semiconductor...
Страница 829: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 830 Freescale Semiconductor O 1 144 LQFP...
Страница 830: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 Freescale Semiconductor 831...
Страница 831: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 832 Freescale Semiconductor...
Страница 832: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 Freescale Semiconductor 833 O 2 100 LQFP...
Страница 833: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 834 Freescale Semiconductor...
Страница 834: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 Freescale Semiconductor 835...
Страница 835: ...Appendix O Package Information S12ZVHY S12ZVHL Family Reference Manual Rev 1 05 836 Freescale Semiconductor...