uart.h

#ifndef __UART_H__
#define __UART_H__

/*########################Constants####################################*/
#define ISR_COUNT 0  // Parameter of using UART handler and buffer(0-off, 1-on)

#define F_CPU    8000000UL  // Frequency of the microcontroller
#define ELEMENTS 512        // UART buffer size
// Erasing the UART buffer
#define BUF_CLEAR                                                \
    {                                                            \
        for (uint16_t i = 0; i < ELEMENTS; buffer_uart[i++] = 0) \
            ;                                                    \
        index_buf = 0;                                           \
    }

// The necessary microcontrollers can be added by yourself
#if (__AVR_ATmega328P__) || (__AVR_ATmega328__) || (__AVR_ATmega644P__) || \
    (__AVR_ATmega644__) || (__AVR_ATmega644A__)
#define MKREG
#endif

/*######################################Functions################################################*/
void uart_init(unsigned long baud);  // Initialization uart
void uart_tr(uint8_t);               // Byte transfering
uint8_t uart_receive_byte();         // Byte recieving
void uart_send(char*);               // Send string
void uart_sendln(char*);             // Send string with "\r\n"

#if ISR_COUNT
void uart_receive();  // Function is inserted into the interrupt with the
                      // vector (USART0_RX_vect)
#endif

#endif