The step 1 and 2 can be sequential or not, but they must be completed before step 3 to
ensure all settings are ready before pulse width measurement is enabled.
41.9 Usage Guide
PWT provides an accurate signal frequency measurement for both the positive and
negative portions of a periodic signal, useful for applications such as motor control. In
conjunction with a Pulse Width Modulated signal it can effectively be used to implement
a highly accurate closed loop motor control system, or any other system in which it might
be necessary to measure a periodic signal frequency and duty cycle, providing not only
accuracy but also high flexibility.
41.9.1 Edge detection, capture control and period measurement
PWT typical usage is external signal input capture and time period measurement.
Example: PWT input channel 1 capture external signal and measure its time period
• Enable the PWT module clock;
• Reset the timer channels and registers;
• Configure not to load the first counter values to corresponding registers, enable the
PWT interrupt;
• Select bus clock as clock source and enable PWT_IN1 as input source;
• Set the module enable bit to start PWT;
• Wait for the pulse width valid flag (PWTRDY) in interrupt routinue, then get the
positive and negative value(PPW, NPW) to calculate the period.
The following pseudo-code matches the described setup above:
CLOCK_EnableClock(PWT);
PWT_CS|= PWT_CS_PWTSR_MASK;
PWT_CS|= PWT_CS_FCTLE(0)|PWT_CS_PWTIE_MASK|PWT_CS_PRDYIE_MASK;
Usage Guide
Kinetis KE1xZ256 Sub-Family Reference Manual, Rev. 3, 07/2018
1050
NXP Semiconductors
Содержание Kinetis KE1xZ256
Страница 2: ...Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 2 NXP Semiconductors...
Страница 56: ...SysTick Clock Configuration Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 56 NXP Semiconductors...
Страница 62: ...Interrupt channel assignments Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 62 NXP Semiconductors...
Страница 124: ...Application information Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 124 NXP Semiconductors...
Страница 130: ...Initialization application information Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 130 NXP Semiconductors...
Страница 178: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 178 NXP Semiconductors...
Страница 356: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 356 NXP Semiconductors...
Страница 368: ...Module clocks Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 368 NXP Semiconductors...
Страница 410: ...Interrupts Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 410 NXP Semiconductors...
Страница 562: ...Power supply supervisor Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 562 NXP Semiconductors...
Страница 592: ...General security features Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 592 NXP Semiconductors...
Страница 604: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 604 NXP Semiconductors...
Страница 622: ...Application Information Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 622 NXP Semiconductors...
Страница 634: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 634 NXP Semiconductors...
Страница 674: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 674 NXP Semiconductors...
Страница 690: ...Module Signal Description Tables Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 690 NXP Semiconductors...
Страница 712: ...Functional description Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 712 NXP Semiconductors...
Страница 820: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 820 NXP Semiconductors...
Страница 1030: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 1030 NXP Semiconductors...
Страница 1052: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 1052 NXP Semiconductors...
Страница 1066: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 1066 NXP Semiconductors...
Страница 1268: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 1268 NXP Semiconductors...
Страница 1314: ...Usage Guide Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 1314 NXP Semiconductors...
Страница 1316: ...Kinetis KE1xZ256 Sub Family Reference Manual Rev 3 07 2018 1316 NXP Semiconductors...