port_thermostat.c

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/* Standard C includes */
#include <stdlib.h>
#include <math.h>
 
/* Project includes */
#include "port_thermostat.h"
 
/* Private functions ---------------------------------------------------------*/
void port_thermostat_timer_setup(fsm_thermostat_t *p_thermostat)
{
 
    if (THERMOSTAT_MEASUREMENT_TIMER == TIM2)
    {
        // Enable the timer clock
        RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;
    }
 
    // Disable the timer
    THERMOSTAT_MEASUREMENT_TIMER->CR1 &= ~TIM_CR1_CEN;
 
    // Autoreload preload enabled
    THERMOSTAT_MEASUREMENT_TIMER->CR1 |= TIM_CR1_ARPE;
 
    // Reset the values of the timer
    THERMOSTAT_MEASUREMENT_TIMER->CNT = 0;
 
    // Set the timeout value
    // Compute ARR and PSC to match the duration. Check if the duration is too long and adapt prescaler and ARR
    double sec = (double)p_thermostat->timer_period_sec;
    double scc = (double)SystemCoreClock;
    double psc = round(((scc * sec) / (65535.0 + 1.0)) - 1.0);
    double arr = round(((scc * sec) / (psc + 1.0)) - 1.0);
 
    // Adjust psc and arr if necessary
    if (arr > 0xFFFF)
    {
        psc += 1.0;
        arr = round((scc * sec) / (psc + 1.0) - 1.0);
    }
 
    // Load the values
    THERMOSTAT_MEASUREMENT_TIMER->ARR = (uint32_t)(round(arr));
    THERMOSTAT_MEASUREMENT_TIMER->PSC = (uint32_t)(round(psc));
 
    // Clean interrupt flags
    THERMOSTAT_MEASUREMENT_TIMER->SR &= ~TIM_SR_UIF;
 
    // Enable the update interrupt
    THERMOSTAT_MEASUREMENT_TIMER->DIER |= TIM_DIER_UIE;
 
    if (THERMOSTAT_MEASUREMENT_TIMER == TIM2)
    {
        // Enable the interrupt in the NVIC
        NVIC_SetPriority(TIM2_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(), 2, 0));
        NVIC_EnableIRQ(TIM2_IRQn);
    }
 
    THERMOSTAT_MEASUREMENT_TIMER->EGR |= TIM_EGR_UG; // 6) Update generation: Re-inicializa el contador y actualiza los registros. IMPORTANTE que esté lo último
 
 
    // Enable the timer
    THERMOSTAT_MEASUREMENT_TIMER->CR1 |= TIM_CR1_CEN;
}