External Interrupt/Event Line Mapping - ST STM32F102 Series Reference Manual

Interrupts and events
An interrupt/event request can also be generated by software by writing a '1' in the software
interrupt/event register.
Hardware interrupt selection
To configure the 19 lines as interrupt sources, use the following procedure:
● Configure the mask bits of the 19 Interrupt lines (EXTI_IMR)
●
Configure the Trigger Selection bits of the Interrupt lines (EXTI_RTSR and
EXTI_FTSR)
●
Configure the enable and mask bits that control the NVIC IRQ channel mapped to the
External Interrupt Controller (EXTI) so that an interrupt coming from one of the 19 lines
can be correctly acknowledged.
Hardware event selection
To configure the 19 lines as event sources, use the following procedure:
●
Configure the mask bits of the 19 Event lines (EXTI_EMR)
●
Configure the Trigger Selection bits of the Event lines (EXTI_RTSR and EXTI_FTSR)
Software interrupt/event selection
The 19 lines can be configured as software interrupt/event lines. The following is the
procedure to generate a software interrupt.
●
Configure the mask bits of the 19 Interrupt/Event lines (EXTI_IMR, EXTI_EMR)
● Set the required bit of the software interrupt register (EXTI_SWIER)
8.2.5

External interrupt/event line mapping

The 112 GPIOs are connected to the 16 external interrupt/event lines in the following
manner:
128/690
RM0008