Auto-wakeup (AWU) RM0016
114/449 Doc ID 14587 Rev 8
12 Auto-wakeup (AWU)
12.1 Introduction
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.
12.2 LSI 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
1. The LS clock source is selected by programming the CKAWUSEL option bit as explained in the clock
controller chapter.
COUNTER
AWU COUNTERS
6-BIT PROG
LSI RC
128 kHz
AWUTB[3:0]
15 time bases
AWU interrupt
AWUEN & HALT/WAIT
MSR
APR[5:0]
Prescaler
~ 128 kHz LS clock
OPTION bit
HSE clock
OPTION bits
PRSC[1:0]
(for measurement)
CKAWUSEL
(1 - 24 MHz)
fLS
fLS
To timer input capture
To Next Page
Loading...
Need help?
General
