ST7LITE49K2 datasheet(126/245 Pages) STMICROELECTRONICS

126 / 245 page

On-chip peripherals

ST7LITE49K2

126/245

Figure 65.

One pulse mode sequence

When a valid event occurs on the ICAP1 pin, the counter value is loaded in the ICR1

and the ICF1 bit is set.

Because the ICF1 bit is set when an active edge occurs, an interrupt can be generated if the

ICIE bit is set.

Clearing the input capture interrupt request (that is, clearing the ICFi bit) is done in two

steps:

Reading the SR register while the ICFi bit is set.

Accessing (reading or writing) the ICiLR register.

The OC1R register value required for a specific timing application can be calculated using

the following formula:

Equation 3

Where:

If the timer clock is an external clock the formula is:

Equation 4

Where:

When the value of the counter is equal to the value of the contents of the OC1R register, the

OLVL1 bit is output on the OCMP1 pin, (see Figure 66).

t =

pulse period (in seconds)

fCPU =

CPU clock frequency (in hertz)

PRESC =

timer prescaler factor (2, 4 or 8 depending on the CC[1:0] bits, see : Timer A

control register 2 (TACR2) on page 132)

t =

pulse period (in seconds)

fEXT =

external timer clock frequency (in hertz)

occurs on

counter

= OC1R

OCMP1 = OLVL1

When

When event

ICAP1

One pulse mode cycle

OCMP1 = OLVL2

Counter is reset

to FFFCh

ICF1 bit is set

ICR1 = counter

OCiR value =

t * fCPU

PRESC

- 5

OCiR=

t * fEXT -5

ST7LITE49K2 数据表(PDF) 126 Page - STMicroelectronics

ST7LITE49K2 数据表(HTML) 126 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