#include "stm32f4xx.h"

// Define the GPIO pins for the 7-segment display (PA0 to PA8 for segments A to G)
#define SEG_A_PIN   (1 << 0)  // PA0
#define SEG_B_PIN   (1 << 1)  // PA1
#define SEG_C_PIN   (1 << 4)  // PA4
#define SEG_D_PIN   (1 << 5)  // PA5
#define SEG_E_PIN   (1 << 6)  // PA6
#define SEG_F_PIN   (1 << 7)  // PA7
#define SEG_G_PIN   (1 << 8)  // PA8

// Define digit control pins (PB0 to PB3 for 4 digits)
#define DIGIT_4_PIN (1 << 0)  // PB0, DIGIT 4
#define DIGIT_3_PIN (1 << 1)  // PB1, DIGIT 3
#define DIGIT_2_PIN (1 << 2)  // PB2, DIGIT 2
#define DIGIT_1_PIN (1 << 5)  // PB5, DIGIT 1

// Corrected segment patterns for digits 9, 0, 3
#define DIGIT_9_PATTERN (SEG_A_PIN | SEG_B_PIN | SEG_C_PIN | SEG_D_PIN | SEG_F_PIN | SEG_G_PIN)  // 9
#define DIGIT_0_PATTERN (SEG_A_PIN | SEG_B_PIN | SEG_C_PIN | SEG_D_PIN | SEG_E_PIN | SEG_F_PIN)  // 0
#define DIGIT_3_PATTERN (SEG_A_PIN | SEG_B_PIN | SEG_C_PIN | SEG_D_PIN | SEG_G_PIN) // 3

// Function to display a digit on the 7-segment display
void display_digit(uint32_t digit_pattern, uint32_t digit_pin) {
    // Turn off all digits
    GPIOB->ODR &= ~(DIGIT_1_PIN | DIGIT_2_PIN | DIGIT_3_PIN | DIGIT_4_PIN);

    // Set the segment pattern for the digit
    GPIOA->ODR &= ~0x1FF;  // Clear PA0-PA8 (segments)
    GPIOA->ODR |= digit_pattern;

    // Turn on the desired digit
    GPIOB->ODR |= digit_pin;
}

// Function for delay to create visible effect
void delay(void) {
    for (volatile int i = 0; i < 1000000; i++);  // Adjust delay for refresh rate
}

int main(void) {
    // Enable GPIOA and GPIOB clocks
    RCC->AHB1ENR |= 0x03;

    // Set PA0-PA8 (segments) and PB0-PB3 (digit control) to output mode
    GPIOA->MODER |= 0x55555555;  // Set PA0, PA1, PA4, PA5, PA6, PA7, PA8 to output mode
    GPIOB->MODER |= 0x55;        // Set PB0, PB1, PB2, PB3 to output mode

    // Time for each digit: 1.33 seconds
    for (int i = 0; i < 2; i++) {
        // Display 9 on digit 2 (PB2)
        display_digit(DIGIT_9_PATTERN, DIGIT_2_PIN);
        delay();

        // Display 0 on digit 3 (PB1)
        display_digit(DIGIT_0_PATTERN, DIGIT_3_PIN);
        delay();

        // Display 3 on digit 4 (PB0)
        display_digit(DIGIT_3_PATTERN, DIGIT_4_PIN);
        delay();
    }

    return 0;
}