#include <stdint.h>
#include <stdio.h>
#include "stm32f103_hal.h"
#include "lcd.h"

volatile uint32_t last_capture = 0;
volatile uint32_t period_ticks = 0;
volatile uint8_t capture_flag = 0;
volatile uint32_t update_ms = 0;

void TIM3_IRQHandler(void) {
    if (TIM3->SR & TIM_SR_CC1IF) {
        uint32_t current_capture = TIM3->CCR1;
        if (current_capture >= last_capture) {
            period_ticks = current_capture - last_capture;
        } else {
            period_ticks = (0xFFFF - last_capture) + current_capture + 1;
        }
        last_capture = current_capture;
        capture_flag = 1;
    }
}

void TIM2_IRQHandler(void) {
    if (TIM2->SR & TIM_SR_UIF) {
        TIM2->SR &= ~TIM_SR_UIF;
        update_ms++;
    }
}

void delay_ms(uint16_t ms) {
    volatile unsigned long t = 0;
    for(uint16_t i = 0; i < ms; i++) {
        for(t = 0; t < 800; t++);
    }
}

int main(void) {
    rcc_clock_enable(RCC_GPIOA);
    rcc_clock_enable(RCC_TIM2);
    rcc_clock_enable(RCC_TIM3);

    GPIOA->CRL &= ~(0xF << (6 * 4));
    GPIOA->CRL |= (0x4 << (6 * 4));

    LCD_Init();
    LCD_Send(LCD_CMD_CLEAR, LCD_MODE_CMD);
    delay_ms(20);
    
    LCD_SetCursor(0, 0);
    LCD_Print("Frecuencimetro");

    TIM3->PSC = 71; 
    TIM3->CCMR1 |= TIM_CCMR1_CC1S_0;
    TIM3->CCER &= ~TIM_CCER_CC1P;
    TIM3->CCER |= TIM_CCER_CC1E;
    TIM3->DIER |= TIM_DIER_CC1IE;
    nvic_enable_irq(TIM3_IRQn);
    TIM3->CR1 |= TIM_CR1_CEN;

    TIM2->PSC = 7199;
    TIM2->ARR = 9;
    TIM2->DIER |= TIM_DIER_UIE;
    nvic_enable_irq(TIM2_IRQn);
    
    nvic_enable();
    TIM2->CR1 |= TIM_CR1_CEN;

    uint32_t freq = 0;
    char buffer[17];

    while (1) {
        if (update_ms >= 100) {
            update_ms = 0;

            if (period_ticks > 0) {
                freq = 1000000 / period_ticks;
            } else {
                freq = 0;
            }

            LCD_SetCursor(0, 1);
            if (freq >= 1000) {
                sprintf(buffer, "F: %lu.%02lu kHz   ", freq / 1000, (freq % 1000) / 10);
            } else {
                sprintf(buffer, "F: %lu Hz      ", freq);
            }
            LCD_Print(buffer);
        }
    }
}