ST10R272L - GENERAL PURPOSE TIMER UNITS
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Note
When programmed for reload mode, the respective auxiliary timer (T2 or T4) stops
independent of its run flag T2R or T4R.
When a trigger signal T3 is loaded with the contents of the respective timer register (T2 or
T4) and the interrupt request flag (T2IR or T4IR) is set.
Note
When a T3OTL transition is selected for the trigger signal, also the interrupt request
flag T3IR will be set upon a trigger, indicating T3’s overflow or underflow.
Modifications of T3OTL via software will NOT trigger the counter function of T2/T4.
The reload mode triggered by T3OTL can be used in a number of different configurations.
Depending on the selected active transition the following functions can be performed:
•
If both a positive and a negative transition of T3OTL is selected to trigger a reload, the
core timer will be reloaded with the contents of the auxiliary timer each time it overflows
or underflows. This is the standard reload mode (reload on overflow/underflow).
•
If either a positive or a negative transition of T3OTL is selected to trigger a reload, the
core timer will be reloaded with the contents of the auxiliary timer on every second
overflow or underflow.
•
Using this “single-transition” mode for both auxiliary timers allows to perform very flexible
pulse width modulation (PWM). One of the auxiliary timers is programmed to reload the
core timer on a positive transition of T3OTL, the other is programmed for a reload on a
Figure 79 GPT1 auxiliary timer in reload mode
*)
Note: Line only affected by over/underflows of T3, but NOT by software modifications of T3OTL.