usart_driver.h File Reference

XMEGA USART driver header file. More...

#include "avr_compiler.h"

Include dependency graph for usart_driver.h:

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Go to the source code of this file.

Data Structures
struct	Usart_and_buffer
	Struct used when interrupt driven driver is used. More...
struct	USART_Buffer

Macros
#define	USART_Baudrate_Set(_usart, _bselValue, _bScaleFactor)
	Set USART baud rate. More...
#define	USART_DreInterruptLevel_Set(_usart, _dreIntLevel)   (_usart)->CTRLA = ((_usart)->CTRLA & ~USART_DREINTLVL_gm) | _dreIntLevel
	Set USART DRE interrupt level. More...
#define	USART_Format_Set(_usart, _charSize, _parityMode, _twoStopBits)
	Macro that sets the USART frame format. More...
#define	USART_GetChar(_usart)   ((_usart)->DATA)
	Get received data (5-8 bit character). More...
#define	USART_IsRXComplete(_usart)   (((_usart)->STATUS & USART_RXCIF_bm) != 0)
	Checks if the RX complete interrupt flag is set. More...
#define	USART_IsTXDataRegisterEmpty(_usart)   (((_usart)->STATUS & USART_DREIF_bm) != 0)
	Check if data register empty flag is set. More...
#define	USART_PutChar(_usart, _data)   ((_usart)->DATA = _data)
	Put data (5-8 bit character). More...
#define	USART_RX_BUFFER_MASK   ( USART_RX_BUFFER_SIZE - 1 )
#define	USART_RX_BUFFER_SIZE   4
#define	USART_Rx_Disable(_usart)   ((_usart)->CTRLB &= ~USART_RXEN_bm)
	Disable USART receiver. More...
#define	USART_Rx_Enable(_usart)   ((_usart)->CTRLB |= USART_RXEN_bm)
	Enable USART receiver. More...
#define	USART_RxdInterruptLevel_Set(_usart, _rxdIntLevel)   ((_usart)->CTRLA = ((_usart)->CTRLA & ~USART_RXCINTLVL_gm) | _rxdIntLevel)
	Set USART RXD interrupt level. More...
#define	USART_SetMode(_usart, _usartMode)   ((_usart)->CTRLC = ((_usart)->CTRLC & (~USART_CMODE_gm)) | _usartMode)
	Set the mode the USART run in. More...
#define	USART_TX_BUFFER_MASK   ( USART_TX_BUFFER_SIZE - 1 )
#define	USART_TX_BUFFER_SIZE   4
#define	USART_Tx_Disable(_usart)   ((_usart)->CTRLB &= ~USART_TXEN_bm)
	Disable USART transmitter. More...
#define	USART_Tx_Enable(_usart)   ((_usart)->CTRLB |= USART_TXEN_bm)
	Enable USART transmitter. More...
#define	USART_TxdInterruptLevel_Set(_usart, _txdIntLevel)   (_usart)->CTRLA = ((_usart)->CTRLA & ~USART_TXCINTLVL_gm) | _txdIntLevel
	Set USART TXD interrupt level. More...

Typedefs
typedef struct USART_Buffer	USART_Buffer_t
typedef struct Usart_and_buffer	USART_data_t
	Struct used when interrupt driven driver is used. More...

Functions
void	USART_DataRegEmpty (USART_data_t *usart_data)
	Data Register Empty Interrupt Service Routine. More...
void	USART_InterruptDriver_DreInterruptLevel_Set (USART_data_t *usart_data, USART_DREINTLVL_t dreIntLevel)
	Set USART DRE interrupt level. More...
void	USART_InterruptDriver_Initialize (USART_data_t *usart_data, USART_t *usart, USART_DREINTLVL_t dreIntLevel)
	Initializes buffer and selects what USART module to use. More...
uint16_t	USART_NineBits_GetChar (USART_t *usart)
	Get received data (9 bit character). More...
void	USART_NineBits_PutChar (USART_t *usart, uint16_t data)
	Put data (9 bit character). More...
uint8_t	USART_RXBuffer_GetByte (USART_data_t *usart_data)
	Get received data (5-8 bit character). More...
bool	USART_RXBufferData_Available (USART_data_t *usart_data)
	Test if there is data in the receive software buffer. More...
bool	USART_RXComplete (USART_data_t *usart_data)
	RX Complete Interrupt Service Routine. More...
bool	USART_TXBuffer_FreeSpace (USART_data_t *usart_data)
	Test if there is data in the transmitter software buffer. More...
bool	USART_TXBuffer_PutByte (USART_data_t *usart_data, uint8_t data)
	Put data (5-8 bit character). More...

Detailed Description

XMEGA USART driver header file.

This file contains the function prototypes and enumerator definitions for various configuration parameters for the XMEGA USART driver.

The driver is not intended for size and/or speed critical code, since most functions are just a few lines of code, and the function call overhead would decrease code performance. The driver is intended for rapid prototyping and documentation purposes for getting started with the XMEGA ADC module.

For size and/or speed critical code, it is recommended to copy the function contents directly into your application instead of making a function call.

Application note:

AVR1307: Using the XMEGA USART

Documentation

For comprehensive code documentation, supported compilers, compiler settings and supported devices see readme.html

Author

Atmel Corporation: http://www.atmel.com
Support email: avr@a.nosp@m.tmel.nosp@m..com

Revision

1694

Date

2008-07-29 14:21:58 +0200 (ti, 29 jul 2008)

Copyright (c) 2008, Atmel Corporation All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
3. The name of ATMEL may not be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Definition in file usart_driver.h.

Macro Definition Documentation

USART_Baudrate_Set

#define USART_Baudrate_Set	(		_usart,
			_bselValue,
			_bScaleFactor
	)

Value:

(_usart)->BAUDCTRLA =(uint8_t)_bselValue;                                           \
    (_usart)->BAUDCTRLB =(_bScaleFactor << USART_BSCALE0_bp)|(_bselValue >> 8)

Set USART baud rate.

Sets the USART's baud rate register.

UBRR_Value : Value written to UBRR ScaleFactor : Time Base Generator Scale Factor

Equation for calculation of BSEL value in asynchronous normal speed mode: If ScaleFactor >= 0 BSEL = ((I/O clock frequency)/(2^(ScaleFactor)*16*Baudrate))-1 If ScaleFactor < 0 BSEL = (1/(2^(ScaleFactor)*16))*(((I/O clock frequency)/Baudrate)-1)

Note

See XMEGA manual for equations for calculation of BSEL value in other modes.

Parameters

_usart	Pointer to the USART module.
_bselValue	Value to write to BSEL part of Baud control register. Use uint16_t type.
_bScaleFactor	USART baud rate scale factor. Use uint8_t type

Definition at line 156 of file usart_driver.h.

USART_DreInterruptLevel_Set

#define USART_DreInterruptLevel_Set	(		_usart,
			_dreIntLevel
	)		(_usart)->CTRLA = ((_usart)->CTRLA & ~USART_DREINTLVL_gm) | _dreIntLevel

Set USART DRE interrupt level.

Sets the interrupt level on Data Register interrupt.

Parameters

_usart	Pointer to the USART module.
_dreIntLevel	Interrupt level of the DRE interrupt. Use USART_DREINTLVL_t type.

Definition at line 222 of file usart_driver.h.

USART_Format_Set

#define USART_Format_Set	(		_usart,
			_charSize,
			_parityMode,
			_twoStopBits
	)

Value:

(_usart)->CTRLC = (uint8_t) _charSize | _parityMode |                      \
                      (_twoStopBits ? USART_SBMODE_bm : 0)

Macro that sets the USART frame format.

Sets the frame format, Frame Size, parity mode and number of stop bits.

Parameters

_usart	Pointer to the USART module
_charSize	The character size. Use USART_CHSIZE_t type.
_parityMode	The parity Mode. Use USART_PMODE_t type.
_twoStopBits	Enable two stop bit mode. Use bool type.

Definition at line 129 of file usart_driver.h.

USART_GetChar

#define USART_GetChar

(

_usart

)

((_usart)->DATA)

Get received data (5-8 bit character).

This macro reads out the RX register. Use the macro USART_RX_Complete to check if anything is received.

Parameters

_usart

The USART module.

Return values

Received

data.

Definition at line 284 of file usart_driver.h.

USART_IsRXComplete

#define USART_IsRXComplete

(

_usart

)

(((_usart)->STATUS & USART_RXCIF_bm) != 0)

Checks if the RX complete interrupt flag is set.

Checks if the RX complete interrupt flag is set.

Parameters

_usart

The USART module.

Definition at line 270 of file usart_driver.h.

USART_IsTXDataRegisterEmpty

#define USART_IsTXDataRegisterEmpty

(

_usart

)

(((_usart)->STATUS & USART_DREIF_bm) != 0)

Check if data register empty flag is set.

Parameters

_usart

The USART module.

Definition at line 248 of file usart_driver.h.

USART_PutChar

#define USART_PutChar	(		_usart,
			_data
	)		((_usart)->DATA = _data)

Put data (5-8 bit character).

Use the macro USART_IsTXDataRegisterEmpty before using this function to put data to the TX register.

Parameters

_usart	The USART module.
_data	The data to send.

Definition at line 260 of file usart_driver.h.

USART_RX_BUFFER_MASK

#define USART_RX_BUFFER_MASK   ( USART_RX_BUFFER_SIZE - 1 )

Definition at line 71 of file usart_driver.h.

Referenced by USART_RXBuffer_GetByte(), and USART_RXComplete().

USART_RX_BUFFER_SIZE

#define USART_RX_BUFFER_SIZE   4

Definition at line 67 of file usart_driver.h.

USART_Rx_Disable

#define USART_Rx_Disable

(

_usart

)

((_usart)->CTRLB &= ~USART_RXEN_bm)

Disable USART receiver.

Parameters

_usart

Pointer to the USART module.

Definition at line 172 of file usart_driver.h.

USART_Rx_Enable

#define USART_Rx_Enable

(

_usart

)

((_usart)->CTRLB |= USART_RXEN_bm)

Enable USART receiver.

Parameters

_usart

Pointer to the USART module

Definition at line 165 of file usart_driver.h.

USART_RxdInterruptLevel_Set

#define USART_RxdInterruptLevel_Set	(		_usart,
			_rxdIntLevel
	)		((_usart)->CTRLA = ((_usart)->CTRLA & ~USART_RXCINTLVL_gm) | _rxdIntLevel)

Set USART RXD interrupt level.

Sets the interrupt level on RX Complete interrupt.

Parameters

_usart	Pointer to the USART module.
_rxdIntLevel	Interrupt level of the RXD interrupt. Use USART_RXCINTLVL_t type.

Definition at line 197 of file usart_driver.h.

USART_SetMode

#define USART_SetMode	(		_usart,
			_usartMode
	)		((_usart)->CTRLC = ((_usart)->CTRLC & (~USART_CMODE_gm)) | _usartMode)

Set the mode the USART run in.

Set the mode the USART run in. The default mode is asynchronous mode.

Parameters

_usart	Pointer to the USART module register section.
_usartMode	Selects the USART mode. Use USART_CMODE_t type.

USART modes:

• 0x0 : Asynchronous mode.
• 0x1 : Synchronous mode.
• 0x2 : IrDA mode.
• 0x3 : Master SPI mode.

Definition at line 239 of file usart_driver.h.

USART_TX_BUFFER_MASK

#define USART_TX_BUFFER_MASK   ( USART_TX_BUFFER_SIZE - 1 )

Definition at line 73 of file usart_driver.h.

Referenced by USART_DataRegEmpty(), USART_TXBuffer_FreeSpace(), and USART_TXBuffer_PutByte().

USART_TX_BUFFER_SIZE

#define USART_TX_BUFFER_SIZE   4

Definition at line 69 of file usart_driver.h.

USART_Tx_Disable

#define USART_Tx_Disable

(

_usart

)

((_usart)->CTRLB &= ~USART_TXEN_bm)

Disable USART transmitter.

Parameters

_usart

Pointer to the USART module.

Definition at line 186 of file usart_driver.h.

USART_Tx_Enable

#define USART_Tx_Enable

(

_usart

)

((_usart)->CTRLB |= USART_TXEN_bm)

Enable USART transmitter.

Parameters

_usart

Pointer to the USART module.

Definition at line 179 of file usart_driver.h.

USART_TxdInterruptLevel_Set

#define USART_TxdInterruptLevel_Set	(		_usart,
			_txdIntLevel
	)		(_usart)->CTRLA = ((_usart)->CTRLA & ~USART_TXCINTLVL_gm) | _txdIntLevel

Set USART TXD interrupt level.

Sets the interrupt level on TX Complete interrupt.

Parameters

_usart	Pointer to the USART module.
_txdIntLevel	Interrupt level of the TXD interrupt. Use USART_TXCINTLVL_t type.

Definition at line 209 of file usart_driver.h.

Typedef Documentation

USART_Buffer_t

typedef struct USART_Buffer USART_Buffer_t

USART_data_t

typedef struct Usart_and_buffer USART_data_t

Struct used when interrupt driven driver is used.

Struct containing pointer to a usart, a buffer and a location to store Data register interrupt level temporary.

Function Documentation

USART_DataRegEmpty()

void USART_DataRegEmpty

(

USART_data_t *

usart_data

)

Data Register Empty Interrupt Service Routine.

Data Register Empty Interrupt Service Routine. Transmits one byte from TX software buffer. Disables DRE interrupt if buffer is empty. Argument is pointer to USART (USART_data_t).

Parameters

usart_data

The USART_data_t struct instance.

Definition at line 260 of file usart_driver.c.

References Usart_and_buffer::buffer, USART_Buffer::TX, USART_Buffer::TX_Head, USART_Buffer::TX_Tail, Usart_and_buffer::usart, and USART_TX_BUFFER_MASK.

{
    USART_Buffer_t * bufPtr;
    bufPtr = &usart_data->buffer;

    /* Check if all data is transmitted. */
    uint8_t tempTX_Tail = usart_data->buffer.TX_Tail;
    if (bufPtr->TX_Head == tempTX_Tail){
        /* Disable DRE interrupts. */
        uint8_t tempCTRLA = usart_data->usart->CTRLA;
        tempCTRLA = (tempCTRLA & ~USART_DREINTLVL_gm) | USART_DREINTLVL_OFF_gc;
        usart_data->usart->CTRLA = tempCTRLA;

    }else{
        /* Start transmitting. */
        uint8_t data = bufPtr->TX[usart_data->buffer.TX_Tail];
        usart_data->usart->DATA = data;

        /* Advance buffer tail. */
        bufPtr->TX_Tail = (bufPtr->TX_Tail + 1) & USART_TX_BUFFER_MASK;
    }
}

USART_InterruptDriver_DreInterruptLevel_Set()

void USART_InterruptDriver_DreInterruptLevel_Set	(	USART_data_t *	usart_data,
		USART_DREINTLVL_t	dreIntLevel
	)

Set USART DRE interrupt level.

Set the interrupt level on Data Register interrupt.

Note

Changing the DRE interrupt level in the interrupt driver while it is running will not change the DRE interrupt level in the USART before the DRE interrupt have been disabled and enabled again.

Parameters

usart_data	The USART_data_t struct instance
dreIntLevel	Interrupt level of the DRE interrupt.

Definition at line 106 of file usart_driver.c.

References Usart_and_buffer::dreIntLevel.

{
    usart_data->dreIntLevel = dreIntLevel;
}

USART_InterruptDriver_Initialize()

void USART_InterruptDriver_Initialize	(	USART_data_t *	usart_data,
		USART_t *	usart,
		USART_DREINTLVL_t	dreIntLevel
	)

Initializes buffer and selects what USART module to use.

Initializes receive and transmit buffer and selects what USART module to use, and stores the data register empty interrupt level.

Parameters

usart_data	The USART_data_t struct instance.
usart	The USART module.
dreIntLevel	Data register empty interrupt level.

Definition at line 81 of file usart_driver.c.

References Usart_and_buffer::buffer, Usart_and_buffer::dreIntLevel, USART_Buffer::RX_Head, USART_Buffer::RX_Tail, USART_Buffer::TX_Head, USART_Buffer::TX_Tail, and Usart_and_buffer::usart.

{
    usart_data->usart = usart;
    usart_data->dreIntLevel = dreIntLevel;

    usart_data->buffer.RX_Tail = 0;
    usart_data->buffer.RX_Head = 0;
    usart_data->buffer.TX_Tail = 0;
    usart_data->buffer.TX_Head = 0;
}

USART_NineBits_GetChar()

uint16_t USART_NineBits_GetChar

(

USART_t *

usart

)

Get received data (9 bit character).

This function reads out the received 9 bit character (uint16_t). Use the function USART_IsRXComplete to check if anything is received.

Parameters

usart

The USART module.

Return values

Received

data.

Definition at line 313 of file usart_driver.c.

{
    if(usart->CTRLB & USART_RXB8_bm) {
        return(0x0100 | usart->DATA);
    }else {
        return(usart->DATA);
    }
}

USART_NineBits_PutChar()

void USART_NineBits_PutChar	(	USART_t *	usart,
		uint16_t	data
	)

Put data (9 bit character).

Use the function USART_IsTXDataRegisterEmpty before using this function to put 9 bit character to the TX register.

Parameters

usart	The USART module.
data	The data to send.

Definition at line 292 of file usart_driver.c.

{
    if(data & 0x0100) {
        usart->CTRLB |= USART_TXB8_bm;
    }else {
        usart->CTRLB &= ~USART_TXB8_bm;
    }

    usart->DATA = (data & 0x00FF);
}

USART_RXBuffer_GetByte()

uint8_t USART_RXBuffer_GetByte

(

USART_data_t *

usart_data

)

Get received data (5-8 bit character).

The function USART_RXBufferData_Available should be used before this function is used to ensure that data is available.

Returns data from RX software buffer.

Parameters

usart_data

The USART_data_t struct instance.

Returns

Received data.

Definition at line 204 of file usart_driver.c.

References Usart_and_buffer::buffer, USART_Buffer::RX, USART_Buffer::RX_Tail, and USART_RX_BUFFER_MASK.

{
    USART_Buffer_t * bufPtr;
    uint8_t ans;

    bufPtr = &usart_data->buffer;
    ans = (bufPtr->RX[bufPtr->RX_Tail]);

    /* Advance buffer tail. */
    bufPtr->RX_Tail = (bufPtr->RX_Tail + 1) & USART_RX_BUFFER_MASK;

    return ans;
}

USART_RXBufferData_Available()

bool USART_RXBufferData_Available

(

USART_data_t *

usart_data

)

Test if there is data in the receive software buffer.

This function can be used to test if there is data in the receive software buffer.

Parameters

usart_data

The USART_data_t struct instance

Return values

true	There is data in the receive buffer.
false	The receive buffer is empty.

Definition at line 181 of file usart_driver.c.

References Usart_and_buffer::buffer, USART_Buffer::RX_Head, and USART_Buffer::RX_Tail.

{
    /* Make copies to make sure that volatile access is specified. */
    uint8_t tempHead = usart_data->buffer.RX_Head;
    uint8_t tempTail = usart_data->buffer.RX_Tail;

    /* There are data left in the buffer unless Head and Tail are equal. */
    return (tempHead != tempTail);
}

USART_RXComplete()

bool USART_RXComplete

(

USART_data_t *

usart_data

)

RX Complete Interrupt Service Routine.

RX Complete Interrupt Service Routine. Stores received data in RX software buffer.

Parameters

usart_data

The USART_data_t struct instance.

Definition at line 227 of file usart_driver.c.

References Usart_and_buffer::buffer, USART_Buffer::RX, USART_Buffer::RX_Head, USART_Buffer::RX_Tail, Usart_and_buffer::usart, and USART_RX_BUFFER_MASK.

{
    USART_Buffer_t * bufPtr;
    bool ans;

    bufPtr = &usart_data->buffer;
    /* Advance buffer head. */
    uint8_t tempRX_Head = (bufPtr->RX_Head + 1) & USART_RX_BUFFER_MASK;

    /* Check for overflow. */
    uint8_t tempRX_Tail = bufPtr->RX_Tail;
    uint8_t data = usart_data->usart->DATA;

    if (tempRX_Head == tempRX_Tail) {
        ans = false;
    }else{
        ans = true;
        usart_data->buffer.RX[usart_data->buffer.RX_Head] = data;
        usart_data->buffer.RX_Head = tempRX_Head;
    }
    return ans;
}

USART_TXBuffer_FreeSpace()

bool USART_TXBuffer_FreeSpace

(

USART_data_t *

usart_data

)

Test if there is data in the transmitter software buffer.

This function can be used to test if there is free space in the transmitter software buffer.

Parameters

usart_data

The USART_data_t struct instance.

Return values

true	There is data in the receive buffer.
false	The receive buffer is empty.

Definition at line 123 of file usart_driver.c.

References Usart_and_buffer::buffer, USART_Buffer::TX_Head, USART_Buffer::TX_Tail, and USART_TX_BUFFER_MASK.

Referenced by USART_TXBuffer_PutByte().

{
    /* Make copies to make sure that volatile access is specified. */
    uint8_t tempHead = (usart_data->buffer.TX_Head + 1) & USART_TX_BUFFER_MASK;
    uint8_t tempTail = usart_data->buffer.TX_Tail;

    /* There are data left in the buffer unless Head and Tail are equal. */
    return (tempHead != tempTail);
}

USART_TXBuffer_PutByte()

bool USART_TXBuffer_PutByte	(	USART_data_t *	usart_data,
		uint8_t	data
	)

Put data (5-8 bit character).

Stores data byte in TX software buffer and enables DRE interrupt if there is free space in the TX software buffer.

Parameters

usart_data	The USART_data_t struct instance.
data	The data to send.

Definition at line 143 of file usart_driver.c.

References Usart_and_buffer::buffer, Usart_and_buffer::dreIntLevel, USART_Buffer::TX, USART_Buffer::TX_Head, Usart_and_buffer::usart, USART_TX_BUFFER_MASK, and USART_TXBuffer_FreeSpace().

{
    uint8_t tempCTRLA;
    uint8_t tempTX_Head;
    bool TXBuffer_FreeSpace;
    USART_Buffer_t * TXbufPtr;

    TXbufPtr = &usart_data->buffer;
    TXBuffer_FreeSpace = USART_TXBuffer_FreeSpace(usart_data);


    if(TXBuffer_FreeSpace)
    {
        tempTX_Head = TXbufPtr->TX_Head;
        TXbufPtr->TX[tempTX_Head]= data;
        /* Advance buffer head. */
        TXbufPtr->TX_Head = (tempTX_Head + 1) & USART_TX_BUFFER_MASK;

        /* Enable DRE interrupt. */
        tempCTRLA = usart_data->usart->CTRLA;
        tempCTRLA = (tempCTRLA & ~USART_DREINTLVL_gm) | usart_data->dreIntLevel;
        usart_data->usart->CTRLA = tempCTRLA;
    }
    return TXBuffer_FreeSpace;
}

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