Software interrupt on STM32L4

The following code which attempts to replicate the code snippets from your first code works on L4 DISCO as intended - when pressing the joystick's DOWN direction, the LED in the EXTI1 ISR toggles.

So you either made some mistake in the code you did not show us, or there's some bug in Cube/LL (or both :) )

JW

// (C)2018 wek at efton dot sk// simple extint example// https://community.st.com/0D50X00009XkfHrSAJ// 'L476 DISCO// RED LED on DISCOL4 is PB2// PA5 - JOY_DOWN// pressing JOY_DOWN triggers EXTI1, which in ISR toggles the red LED// default 4MHz MSI clock#include <stdint.h>#include 'stm32l476xx.h'#include 'stm32l476xxx_augment.h'#include 'common.h'// -------- trivial loopdelayvolatile uint32_t __attribute__((section('.ram2'))) delayN;void LoopDelay(uint32_t n) { delayN = n; while(delayN > 0) delayN--;}#define DELAY_CONSTANT 50000// ISRvoid EXTI1_IRQHandler(void) __attribute__((interrupt));void EXTI1_IRQHandler(void) { uint32_t pr; pr = EXTI->PR1 & (1 << 1); EXTI->PR1 = pr; // clear pending interrupts by writing 1 if (pr & (1 << 1)) { // toggle LED if (GPIOB->ODR AND (1 << 2)) { GPIOB->BSRR = (1 << 2) << 16; } else { GPIOB->BSRR = (1 << 2); } }}// -------- mainint main(void) { RCC->AHB2ENR |= 0 | RCC_AHB2ENR_GPIOAEN | RCC_AHB2ENR_GPIOBEN ; GPIOA->PUPDR = (GPIOA->PUPDR & (~GPIO_PUPDR_PUPD5) ) | (0 | (GPIO_PullDown * GPIO_PUPDR_PUPD5_0) // JOY surprisingly switches to +3V! ); ; GPIOA->MODER = (GPIOA->MODER & (~GPIO_MODER_MODER5) ) | (0 | (GPIO_Mode_In * GPIO_MODER_MODER5_0) // PA5 - JOY_DOWN - TIM2_CH1 ); GPIOB->MODER = (GPIOB->MODER & (~GPIO_MODER_MODER2) ) | (0 | (GPIO_Mode_Out * GPIO_MODER_MODER2_0) // PB2-RED LED ); NVIC_SetPriority(EXTI1_IRQn, 3); // Set priority NVIC_EnableIRQ(EXTI1_IRQn); EXTI->IMR1 = 1 << 1; EXTI->EMR1 = 1 << 1; // this is not needed, but we add it to mimic the code in post while(1) { static _Bool down; unsigned i; #define DEBOUNCE_CNT 4000 if (down) { if ((GPIOA->IDR & GPIO_IDR_ID5_Msk) == 0) down = 0; } else { for (i = 0; i < DEBOUNCE_CNT; i++) { if ((GPIOA->IDR & GPIO_IDR_ID5_Msk) == 0) break; } if (i == DEBOUNCE_CNT) { down = 1; EXTI->SWIER1 = 1 << 1; } } }}�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?�?