Extended interrupts and event controller (EXTI) RM0453
506/1450 RM0453 Rev 5
16 Extended interrupts and event controller (EXTI)
The extended interrupts and event controller (EXTI) manages the individual CPU and
system wake-up through configurable and direct event inputs. It provides wake-up requests
to the power control and generates an interrupt request to the CPU NVIC and events to the
CPU event input.
For each CPU, an additional event Generation block (EVG) is needed to generate the CPU
event signal.
The EXTI wake-up requests allow the system to be woken up from Stop modes and the
CPU to be woken up from the CStop and CStandby modes.
The interrupt request and event request generation can also be used in Run modes.
16.1 EXTI main features
The EXTI main features are the following:
• 47 input events are supported.
• Most event inputs allow the system to be waked up.
• Some events can only be used to generate a CPU wake-up event.
• Events which do not have an associated wake-up flag in the peripheral, have a flag in
the EXTI and generate an interrupt to the CPU from the EXTI.
The asynchronous event inputs are classified in the following two groups:
• Configurable events (signals from I/Os or peripherals able to generate a pulse), with
features listed below:
– Selectable active trigger edge
– Interrupt pending status register bit
– Individual interrupt and event generation mask, used for conditioning the CPU
wake-up, interrupt and event generation
– SW trigger possibility
• Direct events (interrupt and wake-up sources from peripherals, having an associated
flag to be cleared in the peripheral), with features listed below:
– Fixed rising edge active trigger
– No interrupt pending status register bit in the EXTI (The interrupt pending status
flag is provided by the peripheral generating the event.)
– Individual interrupt and event generation mask, used for conditioning the CPU
wake-up and event generation
– No software trigger possibility
16.2 EXTI block diagram
The EXTI consists of a register block accessed via an AHB interface, the event input trigger
block and the masking block as shown in Figure 54.
The register block contains all the EXTI registers.
The event input trigger block provides event input edge trigger logic.
To Next Page
Loading...
Need help?
General
