Posted on November 27, 2017 at 14:20
Hi everyone,
I'm trying to clear my head around interrupts with an STM32l0x3. I'm not using HAL functions, rather I'm trying to understand the logic behind all this.
This becomes a little bit messier since the NVIC registers are not described in the Reference Manual, but in the Programming Manual.
Anyway, working on this I found that for the EXTI the reference manual says:
For the direct interrupt lines: the interrupt is enabled by default in the interrupt mask register and there is no corresponding pending bit in the pending register.
The LPTIM interrupt is a direct line, hence this text applies. LPTIM is interrupt number 29.
PIF29 doesn't exist, and bit 23:31 should be kept at reset value as stated.
However, at the end of ''HAL_LPTIM_IRQHandler(&hlptim1);'' we can find ''__HAL_LPTIM_WAKEUPTIMER_EXTI_CLEAR_FLAG();''
This macro translates to ''EXTI->PR = LPTIM_EXTI_LINE_WAKEUPTIMER_EVENT''
and #define LPTIM_EXTI_LINE_WAKEUPTIMER_EVENT ((uint32_t)EXTI_IMR_IM29)
So, this means that EXTI_PR 29th bit is being set to 1. First of all, as I understand, this has no effect at all. Second, it goes against the reference manual.
Is my understanding correct?
Cheers,Andrés
