High-resolution timer (HRTIM) RM0440
898/2126 RM0440 Rev 4
External event counter
Each timing unit also features an external event counter following the filtering unit, typically
for valley skipping implementation.
The circuitry allows to filter any of the 10 external events filtered, as shown on Figure 226.
Figure 226. External event counter – channel A
The counter is enabled using the EEVACE bit in the HRTIM_EEFxR3 register. This mode is
only valid for edge-sensitive external events (EEASNS[1:0] bit = 01,10 or 11).
The external event is propagated to the timer only if the number of active edges is greater or
equal to the value programmed in (EEVACNT[5:0]+1).
Two operating modes are available:
• when the EEVARSTM bit is reset, the external event counter is reset on each reset/roll-
over event: the external event is active only if it appears several times within a given
PWM period
• when the EEVARSTM/ bit is set, the external event counter is reset only if the event did
not on appear during the last PWM period. This a cumulative mode, where the event
must occur at least once during multiple PWM period, as shown on Figure 227 below.
The external event counter must be enabled after having programmed the counter value
(the EEVACE bit must be set after having written the EEVACNT[5:0] bits).
Once the counter is enabled, the EEVACNT[5:0] bits can then be changed on-the-fly at any
time. The new value is taken into account on the following reset/rollover event as per the
EEVARSTM bit programming, or after a software reset (EEVACRES bit set).
The EEVASEL[3:0]bits must not be modified once the EEVACE bit is set.
MSv47422V1
External event 1
External event 2
External event 3
External event 4
External event 5
External event 6
External event 7
External event 8
External event 9
External event 10
External event 1
External event 2
External event 3
External event 4
External event 5
External event 6
External event 7
External event 8
External event 9
External event 10
Counter external event A
External event A
EEVACNT[5:0]
EEVACRES
EEVARSTM
Reset/
roll-over
event
EEVASEL[3:0]EEVASEL[3:0]
Reset
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