ST STM32L0x3 User Manual

General-purpose timers (TIM2/TIM3) RM0367
526/1043 RM0367 Rev 7
21.4.3 TIMx slave mode control register (TIMx_SMCR)
Address offset: 0x08
Reset value: 0x0000
1514131211109876543210
ETP ECE ETPS[1:0] ETF[3:0] MSM TS[2:0] Res. SMS[2:0]
rw rw rw rw rw rw rw rw rw rw rw rw rw rw rw
Bit 15 ETP: External trigger polarity
This bit selects whether ETR or ETR
is used for trigger operations
0: ETR is noninverted, active at high level or rising edge
1: ETR is inverted, active at low level or falling edge
Bit 14 ECE: External clock enable
This bit enables External clock mode 2.
0: External clock mode 2 disabled
1: External clock mode 2 enabled. The counter is clocked by any active edge on the ETRF
signal.
1: Setting the ECE bit has the same effect as selecting external clock mode 1 with TRGI
connected to ETRF (SMS=111 and TS=111).
2: It is possible to simultaneously use external clock mode 2 with the following slave modes:
reset mode, gated mode and trigger mode. Nevertheless, TRGI must not be connected to
ETRF in this case (TS bits must not be 111).
3: If external clock mode 1 and external clock mode 2 are enabled at the same time, the
external clock input is ETRF.
Bits 13:12 ETPS: External trigger prescaler
External trigger signal ETRP frequency must be at most 1/4 of CK_INT 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

ST STM32L0x3 Specifications

General

Brand	ST
Model	STM32L0x3
Category	Microcontrollers
Language	English