21.3.3.8 PRS Input Triggers
The LETIMER can be configured to start, stop, and/or clear based on PRS inputs. The diagram showing the functions of the PRS input
triggers is shown in
Figure 21.7 LETIMER PRS Input Triggers on page 721
There are 12 PRS inputs to the LETIMER. PRSSTARTSEL, PRSSTOPSEL, and PRSCLEARSEL select which PRS inputs are used to
start, stop, and/or clear the LETIMER. PRSSTARTMODE, PRSSTOPMODE, and PRSCLEARMODE select which edge or edge(s) can
trigger the start, stop, and/or clear action.The PRSSTARTEN, PRSSTOPEN, and PRSCLEAREN signals shown in the diagram are de-
rived from the PRSSTARTMODE, PRSSTOPMODE, and PRSCLEARMODE fields; if the corresponding bit field is set to NONE, the
feature is disabled.
PRS_IN[11:0]
PRSSTARTSEL
LFACLK
LETIMERn
Synchronizer
Edge Detect
PRSSTARTMODE
None
Rising
Falling
Both
PRS_START
PRS_IN[11:0]
PRSSTOPSEL
LFACLK
LETIMERn
Synchronizer
Edge Detect
PRSSTOPMODE
None
Rising
Falling
Both
PRS_STOP
PRS_IN[11:0]
PRSCLEARSEL
LFACLK
LETIMERn
Synchronizer
Edge Detect
PRSCLEARMODE
None
Rising
Falling
Both
PRS_CLEAR
PRSSTARTEN
PRSSTOPEN
PRSCLEAREN
Figure 21.7. LETIMER PRS Input Triggers
21.3.3.9 Debug
If DEBUGRUN in LETIMERn_CTRL is cleared, the LETIMER automatically stops counting when the CPU is halted during a debug ses-
sion, and resumes operation when the CPU continues. Because of synchronization, the LETIMER is halted two clock cycles after the
CPU is halted, and continues running two clock cycles after the CPU continues. RUNNING in LETIMERn_STATUS is not cleared when
the LETIMER stops because of a debug-session.
Set DEBUGRUN in LETIMERn_CTRL to allow the LETIMER to continue counting even when the CPU is halted in debug mode.
Reference Manual
LETIMER - Low Energy Timer
silabs.com
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