Exti Configurable Event Input Wakeup; Exti Direct Event Input Wakeup; Figure 55. Configurable Event Trigger Logic Cpu Wakeup - ST STM32WL5 Series Reference Manual

RM0453
1. Only for input events with configuration "rxev generation" enabled.
16.4.1

EXTI configurable event input wakeup

The extended interrupt/event block diagram for configurable events is shown in
The configurable events allow the system and CPU wakeup from Sleep and Stop modes,
and provide a pending flag in the EXTI.
AHB
Falling Rising
interface
trigger trigger
selection selection
hclk
register register
Configurable
Asynchronous edge
event
detection circuit
input(y)
rst
EXTI
Logic duplicated for each CPU
The software interrupt event register allows configurable events to be triggered by software,
writing the corresponding register bit, irrespective of the edge selection setting.
The rising and falling edges selection registers allow the configurable event active trigger
edge (or both edges) to be enabled.
The CPU has its dedicated interrupt mask and event mask registers. The enabled event
allows the generation of an event on the CPU. All events for a CPU are ORed together into
a single CPU event signal. The event pending register (EXTI_PR) is not set for an
unmasked CPU event.
The configurable events have unique interrupt pending request registers, shared by the
CPU. The pending register is only set for an unmasked interrupt. Each configurable event
provides a common interrupt to the CPU. The configurable event interrupts need to be
acknowledged by software in the EXTI_PR register.
When a CPU interrupt or CPU event is enabled, the asynchronous edge detection circuit is
reset by the clocked delay and rising edge detect pulse generator. This guarantees that the
EXTI hclk clock is woken up before the asynchronous edge detection circuit is reset.
Note: A detected configurable event interrupt pending request may be cleared by the CPU. The
system is not able to enter into low-power modes as long as an interrupt pending request is
active.
16.4.2

EXTI direct event input wakeup

The extended interrupt/event block diagram for direct events is shown in
direct events allow the wakeup of the system and of the CPU from Sleep and Stop modes.

Figure 55. Configurable event trigger logic CPU wakeup

Peripheral interface
Software CPUn
interrupt event
event mask
register register
hclk
Rising
edge
detect
pulse
generator
1) Only for the input events supporting the CPUn rxrev generation cn_event.
Extended interrupts and event controller (EXTI)
CPUn
Pending
interrupt
request
mask
register
register
Other CPUn
Same circuit for configurable
Imask(y)
(1)
CPUn event(y)
CPUn
other events(x,y)
CPUn
other wakeups
CPUn
Other wakeups
wakeup(y)
RM0453 Rev 1
it_exti_per(y)
EVG
and direct events
hclk
cn_evt_rst
Rising edge
cn_evt_exti
detect
rst
hclk
cn_wakeup
sys_wakeup
Figure 56.
Figure 55.
ck_fclk_cn
CPUn rising
edge detect cn_event
pulse
generator
MSv60760V1
The
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