roboot/avr/roboot_if_comm_avr.c

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/* ================================================================================ *//* ================================================================================= */


#include "config.h"
#include <avr/io.h>
#include <util/delay.h>

#include "roboot_if_comm.h"

#define BAUD    BOOTLOADER_USART_SPEED

#if BOOTLOADER_USART == USART_0
#define UBRRH   UBRR0H
#define UBRRL   UBRR0L
#define UCSRA   UCSR0A
#define UCSRB   UCSR0B
#define UCSRC   UCSR0C
#define UDR     UDR0
#elif BOOTLOADER_USART == USART_1
#define UBRRH   UBRR1H
#define UBRRL   UBRR1L
#define UCSRA   UCSR1A
#define UCSRB   UCSR1B
#define UCSRC   UCSR1C
#define UDR     UDR1
#else
#error "Wrong USART configured"
#endif

/**************************************************************************************************\
\**************************************************************************************************/
void CommHwInit(void)
{
    // Stop USART
    UCSRB = 0;

    #include <util/setbaud.h>
    UBRRH = UBRRH_VALUE;
    UBRRL = UBRRL_VALUE;
    UCSRA = 0;
    #if USE_2X
    UCSRA |= (1 << U2X);
    #endif

    UCSRC = _BV(UCSZ1) | _BV(UCSZ0);
    UCSRB = _BV(RXEN) | _BV(TXEN);

    while (UCSRA & _BV(RXC))
    {
        (void) UDR;
    }

}


/**************************************************************************************************\
\**************************************************************************************************/
void CommHwDeinit(void)
{
    // Deinit USART
    UCSRA = 0;
    UCSRB = 0;
    UCSRC = _BV(UCSZ1) | _BV(UCSZ0);
    UBRRH = 0;
    UBRRL = 0;

}

/**************************************************************************************************\
\**************************************************************************************************/
void CommHwSendByte(uint8_t c)
{
    while (0 == (UCSRA & _BV(UDRE)))
    {
        ;
    }

    UDR = c;
}


/**************************************************************************************************\
\**************************************************************************************************/
int16_t CommHwGetByte(void)
{
    uint8_t a_byte;

    if (UCSRA & _BV(RXC))
    {
        a_byte = UDR;
        return a_byte;
    }
    else
    {
        return -1;
    }
}

/**************************************************************************************************\
\**************************************************************************************************/
void MCUBusyDelay(void)
{
    _delay_us(10);
}

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