ST7262 datasheet(47/132 Pages) STMICROELECTRONICS

47 / 132 page

ST7262

47/132

PWM AUTO-RELOAD TIMER (Cont’d)

Input capture function

This mode allows the measurement of external

signal pulse widths through ICRx registers.

Each input capture can generate an interrupt inde-

pendently on a selected input signal transition.

This event is flagged by a set of the corresponding

CFx bits of the Input Capture Control/Status regis-

ter (ICCSR).

These

input

capture

interrupts

are

enabled

through the CIEx bits of the ICCSR register.

The active transition (falling or rising edge) is soft-

ware programmable through the CSx bits of the

ICCSR register.

The read only input capture registers (ICRx) are

used to latch the auto-reload counter value when a

transition is detected on the ARTICx pin (CFx bit

set in ICCSR register). After fetching the interrupt

vector, the CFx flags can be read to identify the in-

terrupt source.

Note: After a capture detection, data transfer in

the ICRx register is inhibited until the ARTICCSR

The timer interrupt remains pending while the CFx

flag is set when the interrupt is enabled (CIEx bit

set). This means, the ARTICCSR register has to

be read at each capture event to clear the CFx

flag.

The timing resolution is given by auto-reload coun-

ter cycle time (1/fCOUNTER).

During HALT mode, input capture is inhibited (the

ICRx is never re-loaded) and only the external in-

terrupt capability can be used.

External interrupt capability

This mode allows the Input capture capabilities to

be used as external interrupt sources.

The edge sensitivity of the external interrupts is

programmable (CSx bit of ICCSR register) and

they are independently enabled through CIEx bits

of the ICCSR register. After fetching the interrupt

vector, the CFx flags can be read to identify the in-

terrupt source.

The interrupts are synchronized on the counter

clock rising edge (Figure 36).

During HALT mode, the external interrupts can still

be used to wake up the micro (if CIEx bit is set).

Figure 36. ART External Interrupt

Figure 37. Input Capture Timing Diagram

ARTICx PIN

CFx FLAG

fCOUNTER

INTERRUPT

COUNTER

01h

fCOUNTER

xxh

02h

03h

04h

05h

06h

07h

04h

ARTICx PIN

CFx FLAG

ICRx REGISTER

INTERRUPT

ST7262 数据表(PDF) 47 Page - STMicroelectronics

ST7262 数据表(HTML) 47 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