Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
Скачиваний:
162
Добавлен:
01.03.2016
Размер:
3.56 Mб
Скачать

Auto-wakeup (AWU)

RM0016

 

 

12 Auto-wakeup (AWU)

12.1Introduction

The AWU is used to provide an internal wakeup time base that is used when the MCU goes into Active-halt power saving mode. This time base is clocked by the low speed internal (LSI) RC oscillator clock or the HSE crystal oscillator clock divided by a prescaler.

12.2LSI clock measurement

To ensure the best possible accuracy when using the LSI clock, its frequency can be measured with TIM3 or TIM1 timer input capture 1 (see datasheet for information on which timer is connected in the specific product).

Figure 25. AWU block diagram

 

 

PRSC[1:0]

CKAWUSEL

 

OPTION bit

 

OPTION bits

 

 

 

HSE clock

 

 

(1 - 24 MHz)

 

MSR

Prescaler

 

 

~ 128 kHz LS clock

To timer input capture

 

 

LSI RC

 

(for measurement)

 

 

128 kHz

 

 

 

fLS

 

APR[5:0]

 

 

fLS

 

 

6-BIT PROG

 

 

COUNTER

 

 

 

AWUTB[3:0]

AWU COUNTERS

 

AWU interrupt

 

15 time bases

 

 

 

AWUEN & HALT/WAIT

1.The LS clock source is selected by programming the CKAWUSEL option bit as explained in the clock controller chapter.

114/454

Doc ID 14587 Rev 9

Соседние файлы в папке Минимум документации STM8_1