This bean implements a pulse-width modulation generator that generates a signal with variable
duty and fixed frequency (period).
After the initialization of the PWM bean, when the bean is disabled (or has not been enabled yet)
the output is set to the value specified by the Initial polarity property.
This value also represents value of the output which is active during the "duty" part of the cycle (tD)
when the bean is enabled and output signal is generated.
For details on timing and initial polarity options please see the pictures below.
Example of generated signal:
Initial polarity is Low, Ratio is 20%
Initial polarity is High, Ratio is 80%
Initial polarity is Low, Ratio is 80%
Initial polarity is High, Ratio is 20%
SetValue and ClrValue methods allow user to control polarity of output signal when the bean doesn't generate the
output (i.e. is disabled or has not been enabled).
Version specific information for HCS12, HCS12X derivatives
Emergency shutdown functionality
Note: This feature may not be available on all HCS12, HCS12X derivatives.
Emergency shutdown functionality is applicable only for Counter that is part of the PWM module.
There are two properties in the bean that influence setting of this feature.
Property Emergency shutdown is mirrored from the CPU bean (for details see the CPU bean properties documentation).
When the Emergency shutdown functionality is enabled and if the Emergency
interrupt service/event is enabled the PWM channel with the highest number is forced to input and the PWM module will generate an emergency shutdown
interrupt when Input active level on this pin is changed. The PWM module stops generation of the output signal, forces
all the output pins to the level se in the Shutdown output level property and it also generates the interrupt.
An event OnShutdown is called when the interrupt is invoked.
Note that event is called always when interrupt is invoked both when the emergency shutdown is asserted and de-asserted.
The bean provides GetShutdownStatus and RestartPWM methods for shutdown status
detection and restarting the PWM signal generation.
See Typical Usage for example service of PWM emergency shutdown.
Sharing of the PWM module emergency shutdown interrupt is not supported. The Emergency interrupt service/event
property can be enabled in only one PPG or PWM bean, although the shutdown stops output signal generation of the whole PWM module.
This bean belongs to the category: CPU Internal Peripherals-Timer
