Demo/msp430_CrossWorks/serial/serial.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd.

     This file is part of the FreeRTOS distribution.

     FreeRTOS is free software; you can redistribute it and/or modify it    under
     the terms of the GNU General Public License (version 2) as published by the
     Free Software Foundation and modified by the FreeRTOS exception.
     **NOTE** The exception to the GPL is included to allow you to distribute a
     combined work that includes FreeRTOS without being obliged to provide the
     source code for proprietary components outside of the FreeRTOS kernel.
     Alternative commercial license and support terms are also available upon
     request.  See the licensing section of http://www.FreeRTOS.org for full
     license details.

     FreeRTOS 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 General Public License for
     more details.

     You should have received a copy of the GNU General Public License along
     with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
     Temple Place, Suite 330, Boston, MA  02111-1307  USA.


     ***************************************************************************
     *                                                                         *
     * The FreeRTOS eBook and reference manual are available to purchase for a *
     * small fee. Help yourself get started quickly while also helping the     *
     * FreeRTOS project! See http://www.FreeRTOS.org/Documentation for details *
     *                                                                         *
     ***************************************************************************

     1 tab == 4 spaces!

     Please ensure to read the configuration and relevant port sections of the
     online documentation.

     http://www.FreeRTOS.org - Documentation, latest information, license and
     contact details.

     http://www.SafeRTOS.com - A version that is certified for use in safety
     critical systems.

     http://www.OpenRTOS.com - Commercial support, development, porting,
     licensing and training services.
 */


 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
  *
  * This file only supports UART 1
  */

 /* Standard includes. */
 #include <stdlib.h>

 /* Scheduler includes. */
 #include "FreeRTOS.h"
 #include "queue.h"
 #include "task.h"

 /* Demo application includes. */
 #include "serial.h"

 /* Constants required to setup the hardware. */
 #define serTX_AND_RX			( ( unsigned char ) 0x03 )

 /* Misc. constants. */
 #define serNO_BLOCK				( ( portTickType ) 0 )

 /* Enable the UART Tx interrupt. */
 #define vInterruptOn() IFG2 |= UTXIFG1

 /* The queue used to hold received characters. */
 static xQueueHandle xRxedChars;

 /* The queue used to hold characters waiting transmission. */
 static xQueueHandle xCharsForTx;

 static volatile short sTHREEmpty;

 /*-----------------------------------------------------------*/

 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
 {
 unsigned long ulBaudRateCount;

 	/* Initialise the hardware. */

 	/* Generate the baud rate constants for the wanted baud rate. */
 	ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;

 	portENTER_CRITICAL();
 	{
 		/* Create the queues used by the com test task. */
 		xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
 		xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );

 		/* Reset UART. */
 		UCTL1 |= SWRST;

 		/* Set pin function. */
 		P4SEL |= serTX_AND_RX;

 		/* All other bits remain at zero for n, 8, 1 interrupt driven operation.
 		LOOPBACK MODE!*/
 		U1CTL |= CHAR + LISTEN;
 		U1TCTL |= SSEL1;

 		/* Setup baud rate low byte. */
 		U1BR0 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );

 		/* Setup baud rate high byte. */
 		ulBaudRateCount >>= 8UL;
 		U1BR1 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );

 		/* Enable ports. */
 		ME2 |= UTXE1 + URXE1;

 		/* Set. */
 		UCTL1 &= ~SWRST;

 		/* Nothing in the buffer yet. */
 		sTHREEmpty = pdTRUE;

 		/* Enable interrupts. */
 		IE2 |= URXIE1 + UTXIE1;
 	}
 	portEXIT_CRITICAL();

 	/* Unlike other ports, this serial code does not allow for more than one
 	com port.  We therefore don't return a pointer to a port structure and can
 	instead just return NULL. */
 	return NULL;
 }
 /*-----------------------------------------------------------*/

 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
 {
 	/* Get the next character from the buffer.  Return false if no characters
 	are available, or arrive before xBlockTime expires. */
 	if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
 	{
 		return pdTRUE;
 	}
 	else
 	{
 		return pdFALSE;
 	}
 }
 /*-----------------------------------------------------------*/

 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
 {
 signed portBASE_TYPE xReturn;

 	/* Transmit a character. */

 	portENTER_CRITICAL();
 	{
 		if( sTHREEmpty == pdTRUE )
 		{
 			/* If sTHREEmpty is true then the UART Tx ISR has indicated that
 			there are no characters queued to be transmitted - so we can
 			write the character directly to the shift Tx register. */
 			sTHREEmpty = pdFALSE;
 			U1TXBUF = cOutChar;
 			xReturn = pdPASS;
 		}
 		else
 		{
 			/* sTHREEmpty is false, so there are still characters waiting to be
 			transmitted.  We have to queue this character so it gets
 			transmitted	in turn. */

 			/* Return false if after the block time there is no room on the Tx
 			queue.  It is ok to block inside a critical section as each task
 			maintains it's own critical section status. */
 			xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );

 			/* Depending on queue sizing and task prioritisation:  While we
 			were blocked waiting to post on the queue interrupts were not
 			disabled.  It is possible that the serial ISR has emptied the
 			Tx queue, in which case we need to start the Tx off again
 			writing directly to the Tx register. */
 			if( ( sTHREEmpty == pdTRUE ) && ( xReturn == pdPASS ) )
 			{
 				/* Get back the character we just posted. */
 				xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
 				sTHREEmpty = pdFALSE;
 				U1TXBUF = cOutChar;
 			}
 		}
 	}
 	portEXIT_CRITICAL();

 	return pdPASS;
 }
 /*-----------------------------------------------------------*/

 #if configINTERRUPT_EXAMPLE_METHOD == 1

 	/*
 	 * UART RX interrupt service routine.
 	 */
 	void vRxISR( void ) __interrupt[ UART1RX_VECTOR ]
 	{
 	signed char cChar;
 	portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

 		/* Get the character from the UART and post it on the queue of Rxed
 		characters. */
 		cChar = U1RXBUF;

 		xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );

 		if( xHigherPriorityTaskWoken )
 		{
 			/*If the post causes a task to wake force a context switch
 			as the woken task may have a higher priority than the task we have
 			interrupted. */
 			taskYIELD();
 		}

         /* Make sure any low power mode bits are clear before leaving the ISR. */
         __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
 	}
 	/*-----------------------------------------------------------*/

 	/*
 	 * UART Tx interrupt service routine.
 	 */
 	void vTxISR( void ) __interrupt[ UART1TX_VECTOR ]
 	{
 	signed char cChar;
 	portBASE_TYPE xTaskWoken = pdFALSE;

 		/* The previous character has been transmitted.  See if there are any
 		further characters waiting transmission. */

 		if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
 		{
 			/* There was another character queued - transmit it now. */
 			U1TXBUF = cChar;
 		}
 		else
 		{
 			/* There were no other characters to transmit. */
 			sTHREEmpty = pdTRUE;
 		}

         /* Make sure any low power mode bits are clear before leaving the ISR. */
         __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
 	}
     /*-----------------------------------------------------------*/

 #elif configINTERRUPT_EXAMPLE_METHOD == 2

     /* This is a standard C function as an assembly file wrapper is used as an
     interrupt entry point. */
 	void vRxISR( void )
 	{
 	signed char cChar;
 	portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

 		/* Get the character from the UART and post it on the queue of Rxed
 		characters. */
 		cChar = U1RXBUF;

 		xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );

         /*If the post causes a task to wake force a context switch
         as the woken task may have a higher priority than the task we have
         interrupted. */
         portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
 	}
 	/*-----------------------------------------------------------*/

     /* This is a standard C function as an assembly file wrapper is used as an
     interrupt entry point. */
 	void vTxISR( void )
 	{
 	signed char cChar;
 	portBASE_TYPE xTaskWoken = pdFALSE;

 		/* The previous character has been transmitted.  See if there are any
 		further characters waiting transmission. */

 		if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
 		{
 			/* There was another character queued - transmit it now. */
 			U1TXBUF = cChar;
 		}
 		else
 		{
 			/* There were no other characters to transmit. */
 			sTHREEmpty = pdTRUE;
 		}
 	}

 #endif /* configINTERRUPT_EXAMPLE_METHOD */
 /*-----------------------------------------------------------*/
	/*
	FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd.

	This file is part of the FreeRTOS distribution.

	FreeRTOS is free software; you can redistribute it and/or modify it under
	the terms of the GNU General Public License (version 2) as published by the
	Free Software Foundation and modified by the FreeRTOS exception.
	NOTE The exception to the GPL is included to allow you to distribute a
	combined work that includes FreeRTOS without being obliged to provide the
	source code for proprietary components outside of the FreeRTOS kernel.
	Alternative commercial license and support terms are also available upon
	request. See the licensing section of http://www.FreeRTOS.org for full
	license details.

	FreeRTOS 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 General Public License for
	more details.

	You should have received a copy of the GNU General Public License along
	with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
	Temple Place, Suite 330, Boston, MA 02111-1307 USA.


	***************************************************************************
	* *
	* The FreeRTOS eBook and reference manual are available to purchase for a *
	* small fee. Help yourself get started quickly while also helping the *
	* FreeRTOS project! See http://www.FreeRTOS.org/Documentation for details *
	* *
	***************************************************************************

	1 tab == 4 spaces!

	Please ensure to read the configuration and relevant port sections of the
	online documentation.

	http://www.FreeRTOS.org - Documentation, latest information, license and
	contact details.

	http://www.SafeRTOS.com - A version that is certified for use in safety
	critical systems.

	http://www.OpenRTOS.com - Commercial support, development, porting,
	licensing and training services.
	*/


	/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
	*
	* This file only supports UART 1
	*/

	/* Standard includes. */
	#include <stdlib.h>

	/* Scheduler includes. */
	#include "FreeRTOS.h"
	#include "queue.h"
	#include "task.h"

	/* Demo application includes. */
	#include "serial.h"

	/* Constants required to setup the hardware. */
	#define serTX_AND_RX ( ( unsigned char ) 0x03 )

	/* Misc. constants. */
	#define serNO_BLOCK ( ( portTickType ) 0 )

	/* Enable the UART Tx interrupt. */
	#define vInterruptOn() IFG2 \|= UTXIFG1

	/* The queue used to hold received characters. */
	static xQueueHandle xRxedChars;

	/* The queue used to hold characters waiting transmission. */
	static xQueueHandle xCharsForTx;

	static volatile short sTHREEmpty;

	/-----------------------------------------------------------/

	xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
	{
	unsigned long ulBaudRateCount;

	/* Initialise the hardware. */

	/* Generate the baud rate constants for the wanted baud rate. */
	ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;

	portENTER_CRITICAL();
	{
	/* Create the queues used by the com test task. */
	xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
	xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );

	/* Reset UART. */
	UCTL1 \|= SWRST;

	/* Set pin function. */
	P4SEL \|= serTX_AND_RX;

	/* All other bits remain at zero for n, 8, 1 interrupt driven operation.
	LOOPBACK MODE!*/
	U1CTL \|= CHAR + LISTEN;
	U1TCTL \|= SSEL1;

	/* Setup baud rate low byte. */
	U1BR0 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );

	/* Setup baud rate high byte. */
	ulBaudRateCount >>= 8UL;
	U1BR1 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );

	/* Enable ports. */
	ME2 \|= UTXE1 + URXE1;

	/* Set. */
	UCTL1 &= ~SWRST;

	/* Nothing in the buffer yet. */
	sTHREEmpty = pdTRUE;

	/* Enable interrupts. */
	IE2 \|= URXIE1 + UTXIE1;
	}
	portEXIT_CRITICAL();

	/* Unlike other ports, this serial code does not allow for more than one
	com port. We therefore don't return a pointer to a port structure and can
	instead just return NULL. */
	return NULL;
	}
	/-----------------------------------------------------------/

	signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
	{
	/* Get the next character from the buffer. Return false if no characters
	are available, or arrive before xBlockTime expires. */
	if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
	{
	return pdTRUE;
	}
	else
	{
	return pdFALSE;
	}
	}
	/-----------------------------------------------------------/

	signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
	{
	signed portBASE_TYPE xReturn;

	/* Transmit a character. */

	portENTER_CRITICAL();
	{
	if( sTHREEmpty == pdTRUE )
	{
	/* If sTHREEmpty is true then the UART Tx ISR has indicated that
	there are no characters queued to be transmitted - so we can
	write the character directly to the shift Tx register. */
	sTHREEmpty = pdFALSE;
	U1TXBUF = cOutChar;
	xReturn = pdPASS;
	}
	else
	{
	/* sTHREEmpty is false, so there are still characters waiting to be
	transmitted. We have to queue this character so it gets
	transmitted in turn. */

	/* Return false if after the block time there is no room on the Tx
	queue. It is ok to block inside a critical section as each task
	maintains it's own critical section status. */
	xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );

	/* Depending on queue sizing and task prioritisation: While we
	were blocked waiting to post on the queue interrupts were not
	disabled. It is possible that the serial ISR has emptied the
	Tx queue, in which case we need to start the Tx off again
	writing directly to the Tx register. */
	if( ( sTHREEmpty == pdTRUE ) && ( xReturn == pdPASS ) )
	{
	/* Get back the character we just posted. */
	xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
	sTHREEmpty = pdFALSE;
	U1TXBUF = cOutChar;
	}
	}
	}
	portEXIT_CRITICAL();

	return pdPASS;
	}
	/-----------------------------------------------------------/

	#if configINTERRUPT_EXAMPLE_METHOD == 1

	/*
	* UART RX interrupt service routine.
	*/
	void vRxISR( void ) __interrupt[ UART1RX_VECTOR ]
	{
	signed char cChar;
	portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* Get the character from the UART and post it on the queue of Rxed
	characters. */
	cChar = U1RXBUF;

	xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );

	if( xHigherPriorityTaskWoken )
	{
	/*If the post causes a task to wake force a context switch
	as the woken task may have a higher priority than the task we have
	interrupted. */
	taskYIELD();
	}

	/* Make sure any low power mode bits are clear before leaving the ISR. */
	__bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
	}
	/-----------------------------------------------------------/

	/*
	* UART Tx interrupt service routine.
	*/
	void vTxISR( void ) __interrupt[ UART1TX_VECTOR ]
	{
	signed char cChar;
	portBASE_TYPE xTaskWoken = pdFALSE;

	/* The previous character has been transmitted. See if there are any
	further characters waiting transmission. */

	if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
	{
	/* There was another character queued - transmit it now. */
	U1TXBUF = cChar;
	}
	else
	{
	/* There were no other characters to transmit. */
	sTHREEmpty = pdTRUE;
	}

	/* Make sure any low power mode bits are clear before leaving the ISR. */
	__bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
	}
	/-----------------------------------------------------------/

	#elif configINTERRUPT_EXAMPLE_METHOD == 2

	/* This is a standard C function as an assembly file wrapper is used as an
	interrupt entry point. */
	void vRxISR( void )
	{
	signed char cChar;
	portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;

	/* Get the character from the UART and post it on the queue of Rxed
	characters. */
	cChar = U1RXBUF;

	xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );

	/*If the post causes a task to wake force a context switch
	as the woken task may have a higher priority than the task we have
	interrupted. */
	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
	}
	/-----------------------------------------------------------/

	/* This is a standard C function as an assembly file wrapper is used as an
	interrupt entry point. */
	void vTxISR( void )
	{
	signed char cChar;
	portBASE_TYPE xTaskWoken = pdFALSE;

	/* The previous character has been transmitted. See if there are any
	further characters waiting transmission. */

	if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
	{
	/* There was another character queued - transmit it now. */
	U1TXBUF = cChar;
	}
	else
	{
	/* There were no other characters to transmit. */
	sTHREEmpty = pdTRUE;
	}
	}

	#endif /* configINTERRUPT_EXAMPLE_METHOD */
	/-----------------------------------------------------------/