Silicon Laboratories EFR32xG14 Wireless Gecko Reference Manual page 720

21.3.3.6 Double Mode
The Double repeat mode works much like the one-shot repeat mode. The difference is that, where the one-shot mode counts as long
as LETIMERn_REP0 is larger than 0, the double mode counts as long as either LETIMERn_REP0 or LETIMERn_REP1 is larger than
0. As an example, say LETIMERn_REP0 is 3 and LETIMERn_REP1 is 10 when the timer is started. If no further interaction is done with
the timer, LETIMERn_REP0 will now be decremented 3 times, and LETIMERn_REP1 will be decremented 10 times. The timer counts a
total of 10 times, and LETIMERn_REP0 is 0 after the first three timer underflows and stays at 0. LETIMERn_REP0 and LETI-
MERn_REP1 can be written at any time. After a write to either of these, the timer is guaranteed to underflow at least the written number
of times if the timer is running. Use the Double repeat mode to generate output on both the LETIMER outputs at the same time. The
state machine for this repeat mode can be seen in
CNT = CNT - 1
CNT = TOP*
21.3.3.7 Clock Source
The LETIMER clock source and its prescaler value are defined in the Clock Management Unit (CMU). The LFACLK
quency given by Figure 21.6 LETIMER Clock Frequency on page
where the exponent LETIMERn is a 4 bit value in the CMU_LFAPRESC0 register.
To use this module, the LE interface clock must be enabled in CMU_HFBUSCLKEN0, in addition to the module clock.
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Figure 21.5 LETIMER Double Repeat State Machine on page
NO
START
NO
YES
NO CNT == 0
YES
REP0 == 0
NO and
REP1 == 0
YES
Figure 21.5. LETIMER Double Repeat State Machine
f
LFACKL_LETIMERn
Figure 21.6. LETIMER Clock Frequency
Wait for positive clock edge
RUNNING
YES
CNT == 0 NO CNT = CNT - 1
YES
CNT = TOP*
REP0 < 2 If (REP0 > 0)
And NO
REP1 < 2 If (REP1 > 0)
YES
STOP = 1
REP0 = 0
TOP*
If (COMP0TOP)
TOP* = COMP0
Else
TOP* = 0xFFFF
720.
LETIMERn
= 32768/2
Reference Manual
LETIMER - Low Energy Timer
720.
If (STOP)
RUNNING = 0
Else if (START)
RUNNING = 1
End if
START = 0
STOP = 0
REP0 = REP0 - 1
REP1 = REP1 - 1
LETIMERn
Rev. 1.1 | 720
has a fre-