RM0312 datasheet(116/275 Pages) STMICROELECTRONICS

116 / 275 page

16-bit general purpose timer (TIM2/TIM3)

RM0312

116/275

DocID022352 Rev 3

Figure 31 shows the behavior of the control circuit and the up-counter in normal mode,

without prescaler.

Figure 31. Control circuit in normal mode, fMASTER divided by 1

17.4.3

External clock source mode 1

The counter can count at each rising or falling edge on a selected timer input. This mode is

selected when SMS=0b111 in the TIMx_SMCR register.

Figure 32. TI2 external clock connection example

For example, to configure the up-counter to count in response to a rising edge on the TI2

input, use the following procedure:

Configure channel 2 to detect rising edges on the TI2 input by writing CC2S= ‘01’ in the

TIMx_CCMR2 register.

Configure the input filter duration by writing the IC2F[3:0] bits in the TIMx_CCMR2

Note:

The capture prescaler is not used for triggering, so you don’t need to configure it. Also you

don’t need to configure the TI2S bits, they only select the input capture source.

Select rising edge polarity by writing CC2P=0 in the TIMx_CCER1 register.

Configure the timer in external clock mode 1 by writing SMS=0b111 in the TIMx_SMCR

Select TI2 as the input source by writing TS=110 in the TIMx_SMCR register.

Enable the counter by writing CEN=1 in the TIMx_CR1 register.

fMASTER

COUNTER CLOCK = CK_CNT = CK_PSC

COUNTER REGISTER

01 02 03 04 05 06 07

32 33 34 35 36

CEN = CNT_EN

CNT_INIT (=UG synchronized: UG or UG+1 clock)

fMASTER

encoder

mode

external clock

mode 1

external clock

mode 2

internal clock

mode

ETRF

TRGI

TI1F

TI2F

(internal clock)

CK_PSC

TIMx_ETR

ECE

TIMx_SMCR

SMS[2:0]

TI1F_ED

TI1FP1

TI2FP2

ETRF

TIMx_SMCR

TS[2:0]

TI2

TIMx_CCER1

CC2P

Filter

ICF[3:0]

TIMx_CCMR2

Edge

Detector

ti2f_rising

ti2f_falling

110

100

101

111

TRGO from other timers

RM0312 数据表(PDF) 116 Page - STMicroelectronics

RM0312 数据表(HTML) 116 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载