FreeRTOS/Demo/CORTEX_STM32F103_GCC_Rowley/Drivers/STM32_USART.c

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*/

/*
	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_PERIOD_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 QueueHandle_t xCharsForTx[ serNUM_COM_PORTS ] = { 0 };

/* Queues holding received characters - one queue per port. */
static QueueHandle_t 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, TickType_t 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, TickType_t 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 )
{
}