flipperzero-firmware/firmware/targets/f7/furi_hal/furi_hal_idle_timer.h

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#pragma once
#include <stm32wbxx_ll_lptim.h>
#include <stm32wbxx_ll_bus.h>
#include <stm32wbxx_ll_rcc.h>
#include <stdint.h>
// Timer used for tickless idle
#define FURI_HAL_IDLE_TIMER_MAX 0xFFFF
#define FURI_HAL_IDLE_TIMER LPTIM2
#define FURI_HAL_IDLE_TIMER_IRQ LPTIM2_IRQn
static inline void furi_hal_idle_timer_init() {
// Configure clock source
LL_RCC_SetLPTIMClockSource(LL_RCC_LPTIM2_CLKSOURCE_LSE);
// Set interrupt priority and enable them
NVIC_SetPriority(
FURI_HAL_IDLE_TIMER_IRQ, NVIC_EncodePriority(NVIC_GetPriorityGrouping(), 15, 0));
NVIC_EnableIRQ(FURI_HAL_IDLE_TIMER_IRQ);
}
static inline void furi_hal_idle_timer_start(uint32_t count) {
count--;
// Enable timer
LL_LPTIM_Enable(FURI_HAL_IDLE_TIMER);
while(!LL_LPTIM_IsEnabled(FURI_HAL_IDLE_TIMER))
;
// Enable compare match interrupt
LL_LPTIM_EnableIT_CMPM(FURI_HAL_IDLE_TIMER);
// Set compare, autoreload and start counter
// Include some marging to workaround ARRM behaviour
LL_LPTIM_SetCompare(FURI_HAL_IDLE_TIMER, count - 3);
LL_LPTIM_SetAutoReload(FURI_HAL_IDLE_TIMER, count);
LL_LPTIM_StartCounter(FURI_HAL_IDLE_TIMER, LL_LPTIM_OPERATING_MODE_ONESHOT);
}
static inline void furi_hal_idle_timer_reset() {
// Hard reset timer
// THE ONLY RELIABLE WAY to stop it according to errata
LL_LPTIM_DeInit(FURI_HAL_IDLE_TIMER);
// Prevent IRQ handler call
NVIC_ClearPendingIRQ(FURI_HAL_IDLE_TIMER_IRQ);
}
static inline uint32_t furi_hal_idle_timer_get_cnt() {
uint32_t counter = LL_LPTIM_GetCounter(FURI_HAL_IDLE_TIMER);
uint32_t counter_shadow = LL_LPTIM_GetCounter(FURI_HAL_IDLE_TIMER);
while(counter != counter_shadow) {
counter = counter_shadow;
counter_shadow = LL_LPTIM_GetCounter(FURI_HAL_IDLE_TIMER);
}
return counter;
}