FreeRTOS/Demo/CORTEX_STM32F103_GCC_Rowley/Drivers/STM32_USART.c - third_party/github/FreeRTOS/FreeRTOS-Kernel - Git at Google

 /*
     FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.

     FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME.  PLEASE VISIT
     http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

     ***************************************************************************
      *                                                                       *
      *    FreeRTOS tutorial books are available in pdf and paperback.        *
      *    Complete, revised, and edited pdf reference manuals are also       *
      *    available.                                                         *
      *                                                                       *
      *    Purchasing FreeRTOS documentation will not only help you, by       *
      *    ensuring you get running as quickly as possible and with an        *
      *    in-depth knowledge of how to use FreeRTOS, it will also help       *
      *    the FreeRTOS project to continue with its mission of providing     *
      *    professional grade, cross platform, de facto standard solutions    *
      *    for microcontrollers - completely free of charge!                  *
      *                                                                       *
      *    >>> See http://www.FreeRTOS.org/Documentation for details. <<<     *
      *                                                                       *
      *    Thank you for using FreeRTOS, and thank you for your support!      *
      *                                                                       *
     ***************************************************************************


     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 modification 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.

     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
     and the FreeRTOS license exception along with FreeRTOS; if not it can be
     viewed here: http://www.freertos.org/a00114.html and also obtained by
     writing to Real Time Engineers Ltd., contact details for whom are available
     on the FreeRTOS WEB site.

     1 tab == 4 spaces!

     ***************************************************************************
      *                                                                       *
      *    Having a problem?  Start by reading the FAQ "My application does   *
      *    not run, what could be wrong?"                                     *
      *                                                                       *
      *    http://www.FreeRTOS.org/FAQHelp.html                               *
      *                                                                       *
     ***************************************************************************


     http://www.FreeRTOS.org - Documentation, books, training, latest versions,
     license and Real Time Engineers Ltd. contact details.

     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
     including FreeRTOS+Trace - an indispensable productivity tool, and our new
     fully thread aware and reentrant UDP/IP stack.

     http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
     Integrity Systems, who sell the code with commercial support,
     indemnification and middleware, under the OpenRTOS brand.

     http://www.SafeRTOS.com - High Integrity Systems also provide a safety
     engineered and independently SIL3 certified version for use in safety and
     mission critical applications that require provable dependability.
 */

 /*
 	INTERRUPT DRIVEN SERIAL PORT DRIVER.
 */


 /******************************************************************************
 *** NOTE:  COM0 == USART1, COM1 == USART2
 ******************************************************************************/


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

 /* Library includes. */
 #include "stm32f10x_lib.h"

 /* Driver includes. */
 #include "STM32_USART.h"
 /*-----------------------------------------------------------*/

 /* The number of COM ports that can be controlled at the same time. */
 #define serNUM_COM_PORTS				( 2 )

 /* Queues are used to hold characters that are waiting to be transmitted.  This
 constant sets the maximum number of characters that can be contained in such a
 queue at any one time. */
 #define serTX_QUEUE_LEN					( 100 )

 /* Queues are used to hold characters that have been received but not yet
 processed.  This constant sets the maximum number of characters that can be
 contained in such a queue. */
 #define serRX_QUEUE_LEN					( 100 )

 /* The maximum amount of time that calls to lSerialPutString() should wait for
 there to be space to post each character to the queue of characters waiting
 transmission.  NOTE!  This is the time to wait per character - not the time to
 wait for the entire string. */
 #define serPUT_STRING_CHAR_DELAY		( 5 / portTICK_RATE_MS )

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

 /* References to the USART peripheral addresses themselves. */
 static USART_TypeDef * const xUARTS[ serNUM_COM_PORTS ] = { ( ( USART_TypeDef * ) USART1_BASE ), ( ( USART_TypeDef * ) USART2_BASE ) };

 /* Queues used to hold characters waiting to be transmitted - one queue per port. */
 static xQueueHandle xCharsForTx[ serNUM_COM_PORTS ] = { 0 };

 /* Queues holding received characters - one queue per port. */
 static xQueueHandle xRxedChars[ serNUM_COM_PORTS ] = { 0 };

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

 /* UART interrupt handlers, as named in the vector table. */
 void USART1_IRQHandler( void );
 void USART2_IRQHandler( void );

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

 /*
  * See header file for parameter descriptions.
  */
 long lCOMPortInit( unsigned long ulPort, unsigned long ulWantedBaud )
 {
 long lReturn = pdFAIL;
 USART_InitTypeDef USART_InitStructure;
 NVIC_InitTypeDef NVIC_InitStructure;
 GPIO_InitTypeDef GPIO_InitStructure;

 	if( ulPort < serNUM_COM_PORTS )
 	{
 		/* The common (not port dependent) part of the initialisation. */
 		USART_InitStructure.USART_BaudRate = ulWantedBaud;
 		USART_InitStructure.USART_WordLength = USART_WordLength_8b;
 		USART_InitStructure.USART_StopBits = USART_StopBits_1;
 		USART_InitStructure.USART_Parity = USART_Parity_No;
 		USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
 		USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
 		NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = configLIBRARY_KERNEL_INTERRUPT_PRIORITY;
 		NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
 		NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;


 		/* Init the buffer structures with the buffer for the COM port being
 		initialised, and perform any non-common initialisation necessary.  This
 		does not check to see if the COM port has already been initialised. */
 		if( ulPort == 0 )
 		{
 			/* Create the queue of chars that are waiting to be sent to COM0. */
 			xCharsForTx[ 0 ] = xQueueCreate( serTX_QUEUE_LEN, sizeof( char ) );

 			/* Create the queue used to hold characters received from COM0. */
 			xRxedChars[ 0 ] = xQueueCreate( serRX_QUEUE_LEN, sizeof( char ) );

 			/* Enable COM0 clock - the ST libraries start numbering from UART1. */
 			RCC_APB2PeriphClockCmd( RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE );

 			/* Configure USART1 Rx (PA10) as input floating */
 			GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
 			GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
 			GPIO_Init( GPIOA, &GPIO_InitStructure );

 			/* Configure USART1 Tx (PA9) as alternate function push-pull */
 			GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
 			GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 			GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
 			GPIO_Init( GPIOA, &GPIO_InitStructure );

 			USART_Init( USART1, &USART_InitStructure );
 			USART_ITConfig( USART1, USART_IT_RXNE, ENABLE );

 			NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQChannel;
 			NVIC_Init( &NVIC_InitStructure );

             USART_DMACmd( USART1, ( USART_DMAReq_Tx | USART_DMAReq_Rx ), ENABLE );
 			USART_Cmd( USART1, ENABLE );

 			/* Everything is ok. */
 			lReturn = pdPASS;
 		}
 		else if( ulPort == 1 )
 		{
 			/* Create the queue of chars that are waiting to be sent to COM1. */
 			xCharsForTx[ 1 ] = xQueueCreate( serTX_QUEUE_LEN, sizeof( char ) );

 			/* Create the queue used to hold characters received from COM0. */
 			xRxedChars[ 1 ] = xQueueCreate( serRX_QUEUE_LEN, sizeof( char ) );

 			/* Enable COM0 clock - the ST libraries start numbering from 1. */
 			RCC_APB2PeriphClockCmd( RCC_APB1Periph_USART2 | RCC_APB2Periph_GPIOA, ENABLE );

 			/* Configure USART2 Rx (PA3) as input floating */
 			GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
 			GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
 			GPIO_Init( GPIOA, &GPIO_InitStructure );

 			/* Configure USART2 Tx (PA2) as alternate function push-pull */
 			GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
 			GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 			GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
 			GPIO_Init( GPIOA, &GPIO_InitStructure );

 			USART_Init( USART2, &USART_InitStructure );
 			USART_ITConfig( USART2, USART_IT_RXNE, ENABLE );

 			NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQChannel;
 			NVIC_Init( &NVIC_InitStructure );

             USART_DMACmd( USART2, ( USART_DMAReq_Tx | USART_DMAReq_Rx ), ENABLE );
 			USART_Cmd( USART2, ENABLE );

 			/* Everything is ok. */
 			lReturn = pdPASS;
 		}
 		else
 		{
 			/* Nothing to do unless more than two ports are supported. */
 		}
 	}

 	return lReturn;
 }
 /*-----------------------------------------------------------*/

 signed long xSerialGetChar( long lPort, signed char *pcRxedChar, portTickType xBlockTime )
 {
 long lReturn = pdFAIL;

 	if( lPort < serNUM_COM_PORTS )
 	{
 		if( xQueueReceive( xRxedChars[ lPort ], pcRxedChar, xBlockTime ) == pdPASS )
 		{
 			lReturn = pdPASS;
 		}
 	}

 	return lReturn;
 }
 /*-----------------------------------------------------------*/

 long lSerialPutString( long lPort, const char * const pcString, unsigned long ulStringLength )
 {
 long lReturn;
 unsigned long ul;

 	if( lPort < serNUM_COM_PORTS )
 	{
 		lReturn = pdPASS;

 		for( ul = 0; ul < ulStringLength; ul++ )
 		{
 			if( xQueueSend( xCharsForTx[ lPort ], &( pcString[ ul ] ), serPUT_STRING_CHAR_DELAY ) != pdPASS )
 			{
 				/* Cannot fit any more in the queue.  Try turning the Tx on to
 				clear some space. */
 				USART_ITConfig( xUARTS[ lPort ], USART_IT_TXE, ENABLE );
 				vTaskDelay( serPUT_STRING_CHAR_DELAY );

 				/* Go back and try again. */
 				continue;
 			}
 		}

         USART_ITConfig( xUARTS[ lPort ], USART_IT_TXE, ENABLE );
 	}
 	else
 	{
 		lReturn = pdFAIL;
 	}

 	return lReturn;
 }
 /*-----------------------------------------------------------*/

 signed long xSerialPutChar( long lPort, signed char cOutChar, portTickType xBlockTime )
 {
 long lReturn;

 	if( xQueueSend( xCharsForTx[ lPort ], &cOutChar, xBlockTime ) == pdPASS )
 	{
 		lReturn = pdPASS;
 		USART_ITConfig( xUARTS[ lPort ], USART_IT_TXE, ENABLE );
 	}
 	else
 	{
 		lReturn = pdFAIL;
 	}

 	return lReturn;
 }
 /*-----------------------------------------------------------*/

 void USART1_IRQHandler( void )
 {
 long xHigherPriorityTaskWoken = pdFALSE;
 char cChar;

 	if( USART_GetITStatus( USART1, USART_IT_TXE ) == SET )
 	{
 		/* The interrupt was caused by the THR becoming empty.  Are there any
 		more characters to transmit? */
 		if( xQueueReceiveFromISR( xCharsForTx[ 0 ], &cChar, &xHigherPriorityTaskWoken ) )
 		{
 			/* A character was retrieved from the buffer so can be sent to the
 			THR now. */
 			USART_SendData( USART1, cChar );
 		}
 		else
 		{
 			USART_ITConfig( USART1, USART_IT_TXE, DISABLE );
 		}
 	}

 	if( USART_GetITStatus( USART1, USART_IT_RXNE ) == SET )
 	{
 		cChar = USART_ReceiveData( USART1 );
 		xQueueSendFromISR( xRxedChars[ 0 ], &cChar, &xHigherPriorityTaskWoken );
 	}

 	portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
 }
 /*-----------------------------------------------------------*/

 void USART2_IRQHandler( void )
 {
 }
	/*
	FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd.

	FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
	http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.

	***************************************************************************
	* *
	* FreeRTOS tutorial books are available in pdf and paperback. *
	* Complete, revised, and edited pdf reference manuals are also *
	* available. *
	* *
	* Purchasing FreeRTOS documentation will not only help you, by *
	* ensuring you get running as quickly as possible and with an *
	* in-depth knowledge of how to use FreeRTOS, it will also help *
	* the FreeRTOS project to continue with its mission of providing *
	* professional grade, cross platform, de facto standard solutions *
	* for microcontrollers - completely free of charge! *
	* *
	* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
	* *
	* Thank you for using FreeRTOS, and thank you for your support! *
	* *
	***************************************************************************


	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 modification 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.

	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
	and the FreeRTOS license exception along with FreeRTOS; if not it can be
	viewed here: http://www.freertos.org/a00114.html and also obtained by
	writing to Real Time Engineers Ltd., contact details for whom are available
	on the FreeRTOS WEB site.

	1 tab == 4 spaces!

	***************************************************************************
	* *
	* Having a problem? Start by reading the FAQ "My application does *
	* not run, what could be wrong?" *
	* *
	* http://www.FreeRTOS.org/FAQHelp.html *
	* *
	***************************************************************************


	http://www.FreeRTOS.org - Documentation, books, training, latest versions,
	license and Real Time Engineers Ltd. contact details.

	http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
	including FreeRTOS+Trace - an indispensable productivity tool, and our new
	fully thread aware and reentrant UDP/IP stack.

	http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
	Integrity Systems, who sell the code with commercial support,
	indemnification and middleware, under the OpenRTOS brand.

	http://www.SafeRTOS.com - High Integrity Systems also provide a safety
	engineered and independently SIL3 certified version for use in safety and
	mission critical applications that require provable dependability.
	*/

	/*
	INTERRUPT DRIVEN SERIAL PORT DRIVER.
	*/


	/******************************************************************************
	*** NOTE: COM0 == USART1, COM1 == USART2
	******************************************************************************/


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

	/* Library includes. */
	#include "stm32f10x_lib.h"

	/* Driver includes. */
	#include "STM32_USART.h"
	/-----------------------------------------------------------/

	/* The number of COM ports that can be controlled at the same time. */
	#define serNUM_COM_PORTS ( 2 )

	/* Queues are used to hold characters that are waiting to be transmitted. This
	constant sets the maximum number of characters that can be contained in such a
	queue at any one time. */
	#define serTX_QUEUE_LEN ( 100 )

	/* Queues are used to hold characters that have been received but not yet
	processed. This constant sets the maximum number of characters that can be
	contained in such a queue. */
	#define serRX_QUEUE_LEN ( 100 )

	/* The maximum amount of time that calls to lSerialPutString() should wait for
	there to be space to post each character to the queue of characters waiting
	transmission. NOTE! This is the time to wait per character - not the time to
	wait for the entire string. */
	#define serPUT_STRING_CHAR_DELAY ( 5 / portTICK_RATE_MS )

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

	/* References to the USART peripheral addresses themselves. */
	static USART_TypeDef * const xUARTS[ serNUM_COM_PORTS ] = { ( ( USART_TypeDef * ) USART1_BASE ), ( ( USART_TypeDef * ) USART2_BASE ) };

	/* Queues used to hold characters waiting to be transmitted - one queue per port. */
	static xQueueHandle xCharsForTx[ serNUM_COM_PORTS ] = { 0 };

	/* Queues holding received characters - one queue per port. */
	static xQueueHandle xRxedChars[ serNUM_COM_PORTS ] = { 0 };

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

	/* UART interrupt handlers, as named in the vector table. */
	void USART1_IRQHandler( void );
	void USART2_IRQHandler( void );

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

	/*
	* See header file for parameter descriptions.
	*/
	long lCOMPortInit( unsigned long ulPort, unsigned long ulWantedBaud )
	{
	long lReturn = pdFAIL;
	USART_InitTypeDef USART_InitStructure;
	NVIC_InitTypeDef NVIC_InitStructure;
	GPIO_InitTypeDef GPIO_InitStructure;

	if( ulPort < serNUM_COM_PORTS )
	{
	/* The common (not port dependent) part of the initialisation. */
	USART_InitStructure.USART_BaudRate = ulWantedBaud;
	USART_InitStructure.USART_WordLength = USART_WordLength_8b;
	USART_InitStructure.USART_StopBits = USART_StopBits_1;
	USART_InitStructure.USART_Parity = USART_Parity_No;
	USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
	USART_InitStructure.USART_Mode = USART_Mode_Rx \| USART_Mode_Tx;
	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = configLIBRARY_KERNEL_INTERRUPT_PRIORITY;
	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;


	/* Init the buffer structures with the buffer for the COM port being
	initialised, and perform any non-common initialisation necessary. This
	does not check to see if the COM port has already been initialised. */
	if( ulPort == 0 )
	{
	/* Create the queue of chars that are waiting to be sent to COM0. */
	xCharsForTx[ 0 ] = xQueueCreate( serTX_QUEUE_LEN, sizeof( char ) );

	/* Create the queue used to hold characters received from COM0. */
	xRxedChars[ 0 ] = xQueueCreate( serRX_QUEUE_LEN, sizeof( char ) );

	/* Enable COM0 clock - the ST libraries start numbering from UART1. */
	RCC_APB2PeriphClockCmd( RCC_APB2Periph_USART1 \| RCC_APB2Periph_GPIOA, ENABLE );

	/* Configure USART1 Rx (PA10) as input floating */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
	GPIO_Init( GPIOA, &GPIO_InitStructure );

	/* Configure USART1 Tx (PA9) as alternate function push-pull */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_Init( GPIOA, &GPIO_InitStructure );

	USART_Init( USART1, &USART_InitStructure );
	USART_ITConfig( USART1, USART_IT_RXNE, ENABLE );

	NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQChannel;
	NVIC_Init( &NVIC_InitStructure );

	USART_DMACmd( USART1, ( USART_DMAReq_Tx \| USART_DMAReq_Rx ), ENABLE );
	USART_Cmd( USART1, ENABLE );

	/* Everything is ok. */
	lReturn = pdPASS;
	}
	else if( ulPort == 1 )
	{
	/* Create the queue of chars that are waiting to be sent to COM1. */
	xCharsForTx[ 1 ] = xQueueCreate( serTX_QUEUE_LEN, sizeof( char ) );

	/* Create the queue used to hold characters received from COM0. */
	xRxedChars[ 1 ] = xQueueCreate( serRX_QUEUE_LEN, sizeof( char ) );

	/* Enable COM0 clock - the ST libraries start numbering from 1. */
	RCC_APB2PeriphClockCmd( RCC_APB1Periph_USART2 \| RCC_APB2Periph_GPIOA, ENABLE );

	/* Configure USART2 Rx (PA3) as input floating */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
	GPIO_Init( GPIOA, &GPIO_InitStructure );

	/* Configure USART2 Tx (PA2) as alternate function push-pull */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_Init( GPIOA, &GPIO_InitStructure );

	USART_Init( USART2, &USART_InitStructure );
	USART_ITConfig( USART2, USART_IT_RXNE, ENABLE );

	NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQChannel;
	NVIC_Init( &NVIC_InitStructure );

	USART_DMACmd( USART2, ( USART_DMAReq_Tx \| USART_DMAReq_Rx ), ENABLE );
	USART_Cmd( USART2, ENABLE );

	/* Everything is ok. */
	lReturn = pdPASS;
	}
	else
	{
	/* Nothing to do unless more than two ports are supported. */
	}
	}

	return lReturn;
	}
	/-----------------------------------------------------------/

	signed long xSerialGetChar( long lPort, signed char *pcRxedChar, portTickType xBlockTime )
	{
	long lReturn = pdFAIL;

	if( lPort < serNUM_COM_PORTS )
	{
	if( xQueueReceive( xRxedChars[ lPort ], pcRxedChar, xBlockTime ) == pdPASS )
	{
	lReturn = pdPASS;
	}
	}

	return lReturn;
	}
	/-----------------------------------------------------------/

	long lSerialPutString( long lPort, const char * const pcString, unsigned long ulStringLength )
	{
	long lReturn;
	unsigned long ul;

	if( lPort < serNUM_COM_PORTS )
	{
	lReturn = pdPASS;

	for( ul = 0; ul < ulStringLength; ul++ )
	{
	if( xQueueSend( xCharsForTx[ lPort ], &( pcString[ ul ] ), serPUT_STRING_CHAR_DELAY ) != pdPASS )
	{
	/* Cannot fit any more in the queue. Try turning the Tx on to
	clear some space. */
	USART_ITConfig( xUARTS[ lPort ], USART_IT_TXE, ENABLE );
	vTaskDelay( serPUT_STRING_CHAR_DELAY );

	/* Go back and try again. */
	continue;
	}
	}

	USART_ITConfig( xUARTS[ lPort ], USART_IT_TXE, ENABLE );
	}
	else
	{
	lReturn = pdFAIL;
	}

	return lReturn;
	}
	/-----------------------------------------------------------/

	signed long xSerialPutChar( long lPort, signed char cOutChar, portTickType xBlockTime )
	{
	long lReturn;

	if( xQueueSend( xCharsForTx[ lPort ], &cOutChar, xBlockTime ) == pdPASS )
	{
	lReturn = pdPASS;
	USART_ITConfig( xUARTS[ lPort ], USART_IT_TXE, ENABLE );
	}
	else
	{
	lReturn = pdFAIL;
	}

	return lReturn;
	}
	/-----------------------------------------------------------/

	void USART1_IRQHandler( void )
	{
	long xHigherPriorityTaskWoken = pdFALSE;
	char cChar;

	if( USART_GetITStatus( USART1, USART_IT_TXE ) == SET )
	{
	/* The interrupt was caused by the THR becoming empty. Are there any
	more characters to transmit? */
	if( xQueueReceiveFromISR( xCharsForTx[ 0 ], &cChar, &xHigherPriorityTaskWoken ) )
	{
	/* A character was retrieved from the buffer so can be sent to the
	THR now. */
	USART_SendData( USART1, cChar );
	}
	else
	{
	USART_ITConfig( USART1, USART_IT_TXE, DISABLE );
	}
	}

	if( USART_GetITStatus( USART1, USART_IT_RXNE ) == SET )
	{
	cChar = USART_ReceiveData( USART1 );
	xQueueSendFromISR( xRxedChars[ 0 ], &cChar, &xHigherPriorityTaskWoken );
	}

	portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
	}
	/-----------------------------------------------------------/

	void USART2_IRQHandler( void )
	{
	}