/**
 * MIDI Footswitch
 *
 * @file   main.h
 * @author Stefan Kalscheuer
 * @date   2014-06-17
 * @brief  USART helper funcitons
 */

/**
 * Initialize USART interface with given BAUD rate.
 *
 * @param baud Baud rate.
 * @return void
 */
void USART_Init(uint32_t baud) {
    /* Calculate UBRR */
    uint16_t ubrr_val = (uint16_t) ((F_CPU / (baud * 16L)) - 1);
    /* Set baud rate */
    UBRRH = (uint8_t) (ubrr_val >> 8);
    UBRRL = (uint8_t) ubrr_val;
    /* Enable transmitter */
    UCSRB |= (1 << TXEN);
    /* Set frame format: 8data, 1stop bit */
    UCSRC = (3 << UCSZ0);
}

/**
 * Receive USART data from buffer.
 *
 * @return Data byte from buffer.
 */
unsigned char USART_Receive(void) {
    /* Wait for data to be received */
    while (!(UCSRA & (1 << RXC)));
    /* Get and return received data from buffer */
    return UDR;
}

/**
 * Transmit USART data byte.
 *
 * @param data Data byte to transmit.
 * @return void
 */
void USART_Transmit(uint8_t data) {
    /* Wait for empty transmit buffer */
    while (!(UCSRA & (1 << UDRE)));
    /* Put data into buffer, sends the data */
    UDR = data;
}

/**
 * Flush USART buffer.
 *
 * @return void
 */
void USART_Flush(void) {
    uint8_t dummy;
    while (UCSRA & (1 << RXC)) {
        dummy = UDR;
    }
}