#include <stm32f103x6.h>
#include <stdio.h>

#define Perpher_CLK 8000000UL
#define Baudrate 115200UL

void uart1_init(void)
{
    RCC->APB2ENR |= RCC_APB2ENR_USART1EN;
    RCC->APB2ENR |= RCC_APB2ENR_USART1EN;

    GPIOA->CRH |= (GPIO_CRH_MODE9 | GPIO_CRH_CNF9_1); // Max op speed is 50MHz, set to alternate functionality
    GPIOA->CRH &= ~GPIO_CRH_CNF9_0;                   // setting the alternate funtion to push pull type

    GPIOA->CRH |= (GPIO_CRH_MODE10 | GPIO_CRH_CNF10_1); // Max op speed is 50MHz, set to alternate functionality
    GPIOA->CRH &= ~GPIO_CRH_CNF10_0;                    // setting the alternate funtion to push pull type

    USART1->CR1 |= RCC_APB2ENR_IOPAEN; // ENABLING THE USART
    USART1->CR1 |= RCC_APB2ENR_AFIOEN;
    USART1->CR1 |= USART_CR1_TE;       // USART1 Transmitter enable
    USART1->CR1 |= USART_CR1_RE;       // USART1 Receiver enable

}

uint16_t compute_uart_bd(uint32_t perif_clk, uint32_t BaudRate)
{
    return ((perif_clk + (BaudRate / 2U)) / BaudRate);
}

void uart_set_baudrate(USART_TypeDef *USARTx, uint32_t perif_clk, uint32_t BaudRate)
{
    USARTx->BRR = compute_uart_bd(perif_clk, BaudRate);
}

void uart1_write(int ch)
{
    // Make sure the transmit data register is empty
    while (!(USART1->SR & USART_SR_TXE))
        ;
    // Write the transmit data register
    USART1->DR = (ch & 0xFF);
}

char uart1_read(void){
    // Make sure the recive data register is not empty
    while (!(USART1->SR & USART_SR_RXNE))
        ;
    return USART1->DR;
}

/*Retargeting printf*/
int __io_putchar(int ch)
{
    uart1_write(ch);
    return ch;
}



int main(void)
{
    char key;
    uart1_init(); // setting the alternate funtion to push pull type
    uart_set_baudrate(USART1, Perpher_CLK, Baudrate);

    while (1)
    {
        uart1_write('y');
        printf("Hello\n");
        key = uart1_read();
        if (key == 'i')
        {
            printf("%s", &key);
        }
    }
}