General-purpose timer (TIMx) RM0008
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Bits 6:4 TS: Trigger Selection.
This bit-field selects the trigger input to be used to synchronize the counter.
000: Internal Trigger 0 (ITR0). TIM1
001: Internal Trigger 1 (ITR1). TIM2
010: Internal Trigger 2 (ITR2). TIM3
011: Internal Trigger 3 (ITR3). TIM4
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 58: TIMx Internal trigger connection on page 314 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 Reserved, always read as 0.
Bits 2:0 SMS: Slave Mode Selection.
When external signals are selected the active edge of the trigger signal (TRGI) is linked to the polarity
selected on the external input (see Input Control register and Control Register description.
000: Slave mode disabled - if CEN = ‘1’ then the prescaler is clocked directly by the internal clock.
001: Encoder mode 1 - Counter counts up/down on TI2FP2 edge depending on TI1FP1 level.
010: Encoder mode 2 - Counter counts up/down on TI1FP1 edge depending on TI2FP2 level.
011: Encoder mode 3 - Counter counts up/down on both TI1FP1 and TI2FP2 edges depending on
the level of the other input.
100: Reset Mode - Rising edge of the selected trigger input (TRGI) reinitializes the counter and
generates an update of the registers.
101: Gated Mode - The counter clock is enabled when the trigger input (TRGI) is high. The counter
stops (but is not reset) as soon as the trigger becomes low. Both start and stop of the counter are
controlled.
110: Trigger Mode - The counter starts at a rising edge of the trigger TRGI (but it is not reset). Only
the start of the counter is controlled.
111: External Clock Mode 1 - Rising edges of the selected trigger (TRGI) clock the counter.
Note: The gated mode must not be used if TI1F_ED is selected as the trigger input (TS=’100’). Indeed,
TI1F_ED outputs 1 pulse for each transition on TI1F, whereas the gated mode checks the level of the
trigger signal.
Table 58. TIMx Internal trigger connection
Slave TIM ITR0 (TS = 000) ITR1 (TS = 001) ITR2 (TS = 010) ITR3 (TS = 011)
TIM2 TIM1 TIM8 TIM3 TIM4
TIM3 TIM1 TIM2 TIM5 TIM4
TIM4 TIM1 TIM2 TIM3 TIM8
TIM5 TIM2 TIM3 TIM4 TIM8