Subversion Repositories idreammicro-avr

/**************************************************************************//**

 * \brief USART0 library

 * \author Copyright (C) 2011  Julien Le Sech - www.idreammicro.com

 * \version 1.0

 * \date 20090426

 *

 * This file is part of the iDreamMicro library.

 *

 * This library is free software: you can redistribute it and/or modify it under

 * the terms of the GNU Lesser General Public License as published by the Free

 * Software Foundation, either version 3 of the License, or (at your option) any

 * later version.

 *

 * This library is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS

 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more

 * details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program. If not, see http://www.gnu.org/licenses/

 ******************************************************************************/

/**************************************************************************//**

 * \file usart0_m328.c

 ******************************************************************************/

/******************************************************************************

 * Header file inclusions.

 ******************************************************************************/

#include "../usart0.h"

#include <usart/usart.h>

#include <useful/bits.h>

#include <avr/interrupt.h>

#include <avr/io.h>

#include <assert.h>

#include <stdbool.h>

#include <stdint.h>

#include <stdlib.h>

/******************************************************************************

 * Private variable declarations.

 ******************************************************************************/

static usart__rx_complete_callback_t*           p_rx_complete           = NULL;

static usart__tx_complete_callback_t*           p_tx_complete           = NULL;

static usart__data_register_empty_callback_t*   p_data_register_empty   = NULL;

static usart__configuration_t configuration =

{

    .mode       = USART__MODE__ASYNCHRONOUS,

    .baudrate   = USART__BAUDRATE__9600,

    .data_size  = USART__DATA_SIZE__8_BITS,

    .stop_size  = USART__STOP_SIZE__1_BIT,

    .parity     = USART__PARITY__DISABLED

};

static bool double_speed_is_set = false;

/******************************************************************************

 * Private function prototypes.

 ******************************************************************************/

/**************************************************************************//**

 * \fn static inline uint16_t usart0__compute_ubrr(void)

 *

 * \brief Compute UBRR register value.

 *

 * \return UBRR value.

 ******************************************************************************/

static inline

uint16_t

usart0__compute_ubrr

(

    void

);

/******************************************************************************

 * Public function definitions.

 ******************************************************************************/

/**************************************************************************//**

 * \fn void usart0__initialize(usart__configuration_t* p_configuration)

 *

 * \brief Initialize USART0.

 *

 * \param[in] p_configuration   USART configuration. If null, default settings

 *                              will be used.

 *

 * Default settings:

 * - baudrate = 9600 bps;

 * - 8 data bits;

 * - 1 stop bit;

 * - no parity.

 ******************************************************************************/

void

usart0__initialize

(

    usart__configuration_t* p_configuration

){

    // If p_configuration is not null, use it!

    if (NULL != p_configuration)

    {

        configuration = *p_configuration;

    }

    // Set mode.

    usart0__set_mode(configuration.mode);

    // Set baud rate.

    usart0__set_baudrate(configuration.baudrate);

    usart0__set_double_speed(false);

    // Configure settings.

    usart0__set_data_size(configuration.data_size);

    usart0__set_stop_size(configuration.stop_size);

    usart0__set_parity(configuration.parity);

}

/**************************************************************************//**

 * \fn void usart0__set_baudrate(usart__baudrate_t baudrate)

 *

 * \brief Set USART0 baudrate.

 *

 * \param baudrate baudrate to set (in bauds per second)

 ******************************************************************************/

void

usart0__set_baudrate

(

    usart__baudrate_t baudrate

){

    configuration.baudrate = baudrate;

    uint16_t ubrr = usart0__compute_ubrr();

    UBRR0H = (uint8_t)(ubrr >> 8);

    UBRR0L = (uint8_t)ubrr;

}

/**************************************************************************//**

 * \fn void usart0__set_mode(usart__mode_t usart_mode)

 *

 * \brief Set USART0 mode.

 *

 * \param usart_mode Mode to set.

 ******************************************************************************/

void

usart0__set_mode

(

    usart__mode_t usart_mode

){

    // Check the preconditions.

    assert(USART__MODE__INVALID > usart_mode);

    configuration.mode = usart_mode;

    switch (usart_mode)

    {

        case USART__MODE__ASYNCHRONOUS:

        {

            BIT__RST(UCSR0C, UMSEL01);

            BIT__RST(UCSR0C, UMSEL00);

        }

        break;

        case USART__MODE__SYNCHRONOUS:

        {

            BIT__RST(UCSR0C, UMSEL01);

            BIT__SET(UCSR0C, UMSEL00);

        }

        break;

        case USART__MODE__MASTER_SPI:

        {

            BIT__SET(UCSR0C, UMSEL01);

            BIT__SET(UCSR0C, UMSEL00);

        }

        break;

        case USART__MODE__INVALID:

        default:

        break;

    }

}

/**************************************************************************//**

 * \fn void usart0__set_data_size(usart__data_sizet data_size)

 *

 * \brief Set USART0 data size.

 *

 * \param data_size data size (in bits)

 ******************************************************************************/

void

usart0__set_data_size

(

    usart__data_size_t data_size

){

    configuration.data_size = data_size;

    switch (data_size)

    {

        case USART__DATA_SIZE__5_BITS:

        {

            BIT__RST(UCSR0B, UCSZ02);

            BIT__RST(UCSR0C, UCSZ01);

            BIT__RST(UCSR0C, UCSZ00);

        }

        break;

        case USART__DATA_SIZE__6_BITS:

        {

            BIT__RST(UCSR0B, UCSZ02);

            BIT__RST(UCSR0C, UCSZ01);

            BIT__SET(UCSR0C, UCSZ00);

        }

        break;

        case USART__DATA_SIZE__7_BITS:

        {

            BIT__RST(UCSR0B, UCSZ02);

            BIT__SET(UCSR0C, UCSZ01);

            BIT__RST(UCSR0C, UCSZ00);

        }

        break;

        case USART__DATA_SIZE__8_BITS:

        {

            BIT__RST(UCSR0B, UCSZ02);

            BIT__SET(UCSR0C, UCSZ01);

            BIT__SET(UCSR0C, UCSZ00);

        }

        break;

        case USART__DATA_SIZE__9_BITS:

        {

            BIT__SET(UCSR0B, UCSZ02);

            BIT__SET(UCSR0C, UCSZ01);

            BIT__SET(UCSR0C, UCSZ00);

        }

        break;

        default:

        break;

    }

}

/**************************************************************************//**

 * \fn void usart0__set_stop_size(usart__stop_size_t stop_size)

 *

 * \brief Set USART0 stop size.

 *

 * \param stop_size stop size (in bits)

 ******************************************************************************/

void

usart0__set_stop_size

(

    usart__stop_size_t stop_size

){

    configuration.stop_size = stop_size;

    if (USART__STOP_SIZE__1_BIT == stop_size)

    {

        BIT__RST(UCSR0C, USBS0);

    }

    else

    {

        BIT__SET(UCSR0C, USBS0);

    }

}

/**************************************************************************//**

 * \fn void usart0__set_parity(usart__parity_t parity)

 *

 * \brief Set USART0 parity.

 *

 * \param parity parity to set

 ******************************************************************************/

void

usart0__set_parity

(

    usart__parity_t parity

){

    configuration.parity = parity;

    switch (parity)

    {

        case USART__PARITY__DISABLED:

        {

            BIT__RST(UCSR0C, UPM01);

            BIT__RST(UCSR0C, UPM00);

        }

        break;

        case USART__PARITY__EVEN:

        {

            BIT__SET(UCSR0C, UPM01);

            BIT__RST(UCSR0C, UPM00);

        }

        break;

        case USART__PARITY__ODD:

        {

            BIT__SET(UCSR0C, UPM01);

            BIT__SET(UCSR0C, UPM00);

        }

        break;

        default:

        break;

    }

}

/**************************************************************************//**

 * \fn void usart0__set_double_speed(bool double_speed)

 *

 * \brief Set double speed.

 *

 * \param   double_speed    True to set double speed, false otherwise.

 ******************************************************************************/

void

usart0__set_double_speed

(

    bool double_speed

){

    double_speed_is_set = double_speed;

    if (double_speed_is_set)

    {

        BIT__SET(UCSR0A, U2X0);

    }

    else

    {

        BIT__RST(UCSR0A, U2X0);

    }

}

/**************************************************************************//**

 * \fn void usart0__enable_receiver(void)

 *

 * \brief Enable USART 0 receiver.

 ******************************************************************************/

void

usart0__enable_receiver

(

    void

){

    BIT__SET(UCSR0B, RXEN0);

}

/**************************************************************************//**

 * \fn void usart0__disable_receiver(void)

 *

 * \brief Disable USART 0 receiver.

 ******************************************************************************/

void

usart0__disable_receiver

(

    void

){

    BIT__RST(UCSR0B, RXEN0);

}

/**************************************************************************//**

 * \fn void usart0__enable_transmitter(void)

 *

 * \brief Enable USART 0 transmitter.

 ******************************************************************************/

void

usart0__enable_transmitter

(

    void

){

    BIT__SET(UCSR0B, TXEN0);

}

/**************************************************************************//**

 * \fn void usart0__disable_transmitter(void)

 *

 * \brief Disable USART 0 transmitter.

 ******************************************************************************/

void

usart0__disable_transmitter

(

    void

){

    BIT__RST(UCSR0B, TXEN0);

}

/**************************************************************************//**

 * \fn uint8_t usart0__receive_byte(void)

 *

 * \brief Receive a byte on USART0.

 *

 * \return received byte

 ******************************************************************************/

uint16_t

usart0__receive_byte

(

    void

){

    // Wait for data to be received.

    while (!(UCSR0A & (1 << RXC0)));

    // Get received data.

    uint16_t received_byte = UDR0;

    if (USART__DATA_SIZE__9_BITS == configuration.data_size)

    {

        // If 9-bit data size, get 9th bit.

        uint8_t resh = UCSR0B;

        resh = (resh >> 1) & 0x01;

        received_byte = (resh << 8) | received_byte;

    }

    // Return received data from buffer.

    return received_byte;

}

/**************************************************************************//**

 * \fn usart0__transmit_byte(uint8_t byte_to_transmit)

 *

 * \brief Transmit a byte on USART0.

 *

 * \param byte_to_transmit byte to transmit

 ******************************************************************************/

void

usart0__transmit_byte

(

    uint16_t byte_to_transmit

){

    // Wait for empty transmit buffer.

    while (!(UCSR0A & (1 << UDRE0)));

    if (USART__DATA_SIZE__9_BITS == configuration.data_size)

    {

        // If 9-bit data size, copy 9th bit to TXB80.

        UCSR0B &= ~(1 << TXB80);

        if (byte_to_transmit & 0x0100)

        {

            UCSR0B |= (1 << TXB80);

        }

    }

    // Put data into transmit buffer, sends the data.

    UDR0 = byte_to_transmit;

}

/**************************************************************************//**

 * \fn void usart0__flush(void)

 *

 * \brief Flush USART0 receiver buffer.

 ******************************************************************************/

void

usart0__flush

(

    void

){

    uint8_t dummy = 0;

    while (UCSR0A & (1 << RXC0))

    {

        dummy = UDR0;

    }

}

/**************************************************************************//**

 * \fn void usart0__enable_rx_complete_interrupt(void)

 *

 * \brief Enable USART 0 receive complete interrupt.

 ******************************************************************************/

void

usart0__enable_rx_complete_interrupt

(

    void

){

    BIT__SET(UCSR0B, RXCIE0);

    sei();

}

/**************************************************************************//**

 * \fn void usart0__disable_rx_complete_interrupt(void)

 *

 * \brief Disable USART 0 receive complete interrupt.

 ******************************************************************************/

void

usart0__disable_rx_complete_interrupt

(

    void

){

    BIT__RST(UCSR0B, RXCIE0);

    sei();

}

/**************************************************************************//**

 * \fn void usart0__set_rx_complete_callback(

 * const usart__rx_complete_callback_t* p_callback)

 *

 * \brief Set a callback to call when receive byte complete interrupt is

 * generated.

 *

 * \param[in]   p_callback  Callback to set.

 ******************************************************************************/

void

usart0__set_rx_complete_callback

(

    const usart__rx_complete_callback_t*  p_callback

){

    // Check the preconditions.

    assert(NULL != p_callback);

    p_rx_complete = p_callback;

}

/**************************************************************************//**

 * \fn void usart0__enable_tx_complete_interrupt(void)

 *

 * \brief Enable interrupt when TX complete.

 ******************************************************************************/

void

usart0__enable_tx_complete_interrupt

(

    void

){

    BIT__SET(UCSR0B, TXCIE0);

    sei();

}

/**************************************************************************//**

 * \fn void usart0__disable_tx_complete_interrupt(void)

 *

 * \brief Disable interrupt when TX complete.

 ******************************************************************************/

void

usart0__disable_tx_complete_interrupt

(

    void

){

    BIT__RST(UCSR0B, TXCIE0);

    sei();

}

/**************************************************************************//**

 * \fn void usart0__set_tx_complete_callback(

 * const usart__tx_complete_callback_t*  p_callback)

 *

 * \brief Set a callback to call when TX is complete.

 *

 * \param[in] p_callback        Function to call.

 ******************************************************************************/

void

usart0__set_tx_complete_callback

(

    const usart__tx_complete_callback_t*  p_callback

){

    // Check the preconditions.

    assert(NULL != p_callback);

    p_tx_complete = p_callback;

}

/**************************************************************************//**

 * \fn void usart0__enable_data_register_empty_interrupt()

 *

 * \brief Enable interrupt when data register is empty.

 ******************************************************************************/

void

usart0__enable_data_register_empty_interrupt

(

    void

){

    BIT__SET(UCSR0B, UDRIE0);

    sei();

}

/**************************************************************************//**

 * \fn void usart0__disable_data_register_empty_interrupt()

 *

 * \brief Disable interrupt when data register is empty.

 ******************************************************************************/

void

usart0__disable_data_register_empty_interrupt

(

    void

){

    BIT__RST(UCSR0B, UDRIE0);

    sei();

}

/**************************************************************************//**

 * \fn void usart0__set_data_register_empty_callback(

 * const usart__data_register_empty_callback_t*  p_callback)

 *

 * \brief Set a callback to call when data register is empty.

 *

 * \param[in] p_callback        Function to call.

 ******************************************************************************/

void

usart0__set_data_register_empty_callback

(

    const usart__data_register_empty_callback_t*  p_callback

){

    // Check the preconditions.

    assert(NULL != p_callback);

    p_data_register_empty = p_callback;

}

/******************************************************************************

 * Private function definitions.

 ******************************************************************************/

/**************************************************************************//**

 * \fn static inline uint16_t usart0__compute_ubrr(void)

 *

 * \brief Compute UBRR register value.

 *

 * \return UBRR value.

 ******************************************************************************/

static inline

uint16_t

usart0__compute_ubrr

(

    void

){

    uint16_t ubrr = 0;

    switch (configuration.mode)

    {

        case USART__MODE__ASYNCHRONOUS:

        {

            if (!double_speed_is_set)

            {

                ubrr = F_CPU / (16 * configuration.baudrate) - 1;

            }

            else

            {

                ubrr = F_CPU / (8 * configuration.baudrate) - 1;

            }

        }

        break;

        case USART__MODE__SYNCHRONOUS:

        {

            ubrr = F_CPU / (2 * configuration.baudrate) - 1;

        }

        break;

        case USART__MODE__MASTER_SPI:

        break;

        default:

        break;

    }

    return ubrr;

}

/******************************************************************************

 * Interrupt vectors.

 ******************************************************************************/

/**************************************************************************//**

 * \fn ISR(USART_RX_vect)

 *

 * \brief RX interrupt vector.

 ******************************************************************************/

ISR(USART_RX_vect)

{

    if (NULL != p_rx_complete)

    {

        p_rx_complete();

    }

}

/**************************************************************************//**

 * \fn ISR(USART_TX_vect)

 *

 * \brief TX interrupt vector.

 ******************************************************************************/

ISR(USART_TX_vect)

{

    if (NULL != p_tx_complete)

    {

        p_tx_complete();

    }

}

/**************************************************************************//**

 * \fn ISR(USART_UDRE_vect)

 *

 * \brief Data register empty interrupt vector.

 ******************************************************************************/

ISR(USART_UDRE_vect)

{

    if (NULL != p_data_register_empty)

    {

        p_data_register_empty();

    }

}