buzzer.c

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#include "buzzer.h"
#include "main.h" // Needed for HAL_Delay and timer register macros.
 
// --- Private Constants ---
// Define these here to avoid cluttering the header. Adjust if your system clock changes.
#define TIMER_CLOCK_FREQ    240000000UL  
#define TIMER_PRESCALER     2400         
 
// --- Global Variable Definition ---
buzzer_t buzzer;
 
void buzzer_init(buzzer_t *bz, TIM_HandleTypeDef *htim, uint32_t channel)
{
    // Assert that the provided pointers are valid.
    if (bz == NULL || htim == NULL) {
        Error_Handler();
    }
 
    bz->htim = htim;
    bz->tim_channel = channel;
}
 
void musica_maestro(buzzer_t *bz, const note_t *partition, uint16_t melody_length)
{
    if (bz == NULL || bz->htim == NULL || partition == NULL) {
        return; // Safety check
    }
 
    // Start the PWM signal. The duty cycle is set to 50% by configuring ARR/2.
    HAL_TIM_PWM_Start(bz->htim, bz->tim_channel);
 
    for (uint16_t i = 0; i < melody_length; i++) {
        uint16_t freq = partition[i].frequency;
        uint16_t duration = partition[i].duration_ms;
 
        if (freq == REST || duration == 0) {
            // Silence for a rest note
            __HAL_TIM_SET_COMPARE(bz->htim, bz->tim_channel, 0); // Set duty cycle to 0% for silence
            if (duration > 0) {
                HAL_Delay(duration);
            }
        } else {
            // Play a tone
            // Calculate the Auto-Reload Register (ARR) value for the desired frequency
            uint32_t arr_value = (TIMER_CLOCK_FREQ / (TIMER_PRESCALER * freq)) - 1;
 
            // Clamp the ARR value to the 16-bit timer limit
            if (arr_value > 0xFFFF) {
                arr_value = 0xFFFF;
            }
 
            // Set the timer period (determines frequency)
            __HAL_TIM_SET_AUTORELOAD(bz->htim, arr_value);
            // Set the duty cycle to 50% for a standard tone
            __HAL_TIM_SET_COMPARE(bz->htim, bz->tim_channel, arr_value / 2);
 
            // Hold the note for its duration
            HAL_Delay(duration);
        }
    }
 
    // Stop the PWM signal after the melody is finished
    HAL_TIM_PWM_Stop(bz->htim, bz->tim_channel);
}