#include "stm32c0xx.h"

// Function prototypes
void UART1_Init(void);
void UART1_Receive(void);
void LED_Init(void);
void LED_On(void);
void LED_Off(void);

char received_data[100];
volatile int index_1 = 0;

int main(void) {
    UART1_Init();
    LED_Init();
    Serial.begin(115200);
    Serial.print("hello");
    while (1) {
        UART1_Receive(); // Receive data from UART
        
        // Check the received command and control LED accordingly
        if (received_data[0] == 'O' && received_data[1] == 'N' && received_data[2] == '\0') {
            LED_On();
        } else if (received_data[0] == 'O' && received_data[1] == 'F' && received_data[2] == 'F' && received_data[3] == '\0') {
            LED_Off();
        }
        
        // Clear received data buffer
        for (int i = 0; i < 100; i++) {
            received_data[i] = 0;
        }
        index_1 = 0;
    }
}

void UART1_Init(void) {
    // Enable GPIOA and USART1 clocks
    RCC->AHBENR |= RCC_IOPENR_GPIOAEN;
    RCC->AHBENR |= RCC_APBENR2_USART1EN;
    
    // Configure PA2 (TX) and PA3 (RX) for USART1
    GPIOA->MODER &= ~(GPIO_MODER_MODE2 | GPIO_MODER_MODE3); // Clear mode bits
    GPIOA->MODER |= (GPIO_MODER_MODE2_1 | GPIO_MODER_MODE3_1); // Set to alternate function mode
    GPIOA->AFR[0] |= (4 << GPIO_AFRL_AFSEL2_Pos) | (4 << GPIO_AFRL_AFSEL3_Pos); // AF4 for USART1

    // Configure USART1
    USART1->BRR = 0x1A1; // Baud rate 115200 (assuming 16MHz clock, adjust if different)
    USART1->CR1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_UE; // Enable TX, RX, and USART
}

void UART1_Receive(void) {
    while (!(USART1->ISR & USART_ISR_NE)); // Wait until RXNE (Receive Data Register Not Empty) is set
    received_data[index_1++] = USART1->RDR; // Read received data
    if (received_data[index_1-1] == '\n' || index_1 >= 100) { // End of command or buffer full
        received_data[index_1-1] = '\0'; // Null-terminate the string
        index_1= 0; // Reset index
    }
}

void LED_Init(void) {
    // Enable GPIOA clock
    RCC->AHBENR |= RCC_IOPENR_GPIOAEN;
    
    // Configure PA5 as output
    GPIOA->MODER &= ~GPIO_MODER_MODE5; // Clear mode bits for PA5
    GPIOA->MODER |= GPIO_MODER_MODE5_0; // Set to general purpose output mode
}

void LED_On(void) {
    GPIOA->ODR |= GPIO_ODR_OD5; // Set PA5 high
}

void LED_Off(void) {
    GPIOA->ODR &= ~GPIO_ODR_OD5; // Set PA5 low
}