ST STM32L4 5 Series User Manual

DocID024597 Rev 5 941/1830
RM0351 Advanced-control timers (TIM1/TIM8)
981
Bits 13:12 ETPS[1:0]: External trigger prescaler
External trigger signal ETRP frequency must be at most 1/4 of TIMxCLK frequency. A
prescaler can be enabled to reduce ETRP frequency. It is useful when inputting fast external
clocks.
00: Prescaler OFF
01: ETRP frequency divided by 2
10: ETRP frequency divided by 4
11: ETRP frequency divided by 8
Bits 11:8 ETF[3:0]: External trigger filter
This bit-field then defines the frequency used to sample ETRP signal and the length of the
digital filter applied to ETRP. The digital filter is made of an event counter in which N
consecutive events are needed to validate a transition on the output:
0000: No filter, sampling is done at f
DTS
0001: f
SAMPLING
=f
CK_INT
, N=2
0010: f
SAMPLING
=f
CK_INT
, N=4
0011: f
SAMPLING
=f
CK_INT
, N=8
0100: f
SAMPLING
=f
DTS
/2, N=6
0101: f
SAMPLING
=f
DTS
/2, N=8
0110: f
SAMPLING
=f
DTS
/4, N=6
0111: f
SAMPLING
=f
DTS
/4, N=8
1000: f
SAMPLING
=f
DTS
/8, N=6
1001: f
SAMPLING
=f
DTS
/8, N=8
1010: f
SAMPLING
=f
DTS
/16, N=5
1011: f
SAMPLING
=f
DTS
/16, N=6
1100: f
SAMPLING
=f
DTS
/16, N=8
1101: f
SAMPLING
=f
DTS
/32, N=5
1110: f
SAMPLING
=f
DTS
/32, N=6
1111: f
SAMPLING
=f
DTS
/32, N=8
Bit 7 MSM: Master/slave mode
0: No action
1: The effect of an event on the trigger input (TRGI) is delayed to allow a perfect
synchronization between the current timer and its slaves (through TRGO). It is useful if we
want to synchronize several timers on a single external event.
Bits 6:4 TS[2:0]: Trigger selection
This bit-field selects the trigger input to be used to synchronize the counter.
000: Internal Trigger 0 (ITR0)
001: Internal Trigger 1 (ITR1)
010: Internal Trigger 2 (ITR2)
011: Internal Trigger 3 (ITR3)
100: TI1 Edge Detector (TI1F_ED)
101: Filtered Timer Input 1 (TI1FP1)
110: Filtered Timer Input 2 (TI2FP2)
111: External Trigger input (ETRF)
See Table 187: TIMx internal trigger connection on page 942 for more details on ITRx
meaning for each Timer.
Note: These bits must be changed only when they are not used (e.g. when SMS=000) to
avoid wrong edge detections at the transition.
Bit 3 OCCS: OCREF clear selection
This bit is used to select the OCREF clear source.
0: OCREF_CLR_INT is not connected (reserved configuration)
1: OCREF_CLR_INT is connected to ETRF

ST STM32L4 5 Series Specifications

General

Brand	ST
Model	STM32L4 5 Series
Category	Microcontrollers
Language	English