serial.c

430上实现简单的web服务器

/*
	FreeRTOS V2.5.5 - Copyright (C) 2003 - 2005 Richard Barry.

	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 as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	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

	A special exception to the GPL can be applied should you wish to distribute
	a combined work that includes FreeRTOS, without being obliged to provide
	the source code for any proprietary components.  See the licensing section 
	of http://www.FreeRTOS.org for full details of how and when the exception
	can be applied.

	***************************************************************************
	See http://www.FreeRTOS.org for documentation, latest information, license 
	and contact details.  Please ensure to read the configuration and relevant 
	port sections of the online documentation.
	***************************************************************************
*/


/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.   
 * 
 * This file only supports UART 0
 */

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

/* Scheduler includes. */
#include "projdefs.h"
#include "portable.h"
#include "queue.h"
#include "task.h"

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

/* Constants required to setup the hardware. */
#define serTX_AND_RX			( ( unsigned portCHAR ) BIT4 | BIT5 )

/* The UART runs of the ACLK, which is also drives the tick timer.
 * Refer to prvSetupTimerInterrupt() to see how this works. */
#define portACLK_FREQUENCY_HZ     (portCPU_CLOCK_HZ / 8)

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

/* Enable the UART Tx interrupt. */
// #define vInterruptOn() IFG2 |= UTXIFG0

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

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

static volatile portSHORT sTHREEmpty;

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

xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portCHAR ucQueueLength )
{
unsigned portLONG ulBaudRateCount;
unsigned portCHAR ucByte;

	/* Initialise the hardware. */

	/* Generate the baud rate constants for the wanted baud rate. */
	ulBaudRateCount = portACLK_FREQUENCY_HZ / ulWantedBaud;
  
	portENTER_CRITICAL();
	{
		/* Create the queues used by the com test task. */
		xRxedChars = xQueueCreate( ucQueueLength, ( unsigned portCHAR ) sizeof( signed portCHAR ) );
		xCharsForTx = xQueueCreate( ucQueueLength, ( unsigned portCHAR ) sizeof( signed portCHAR ) );

		/* Reset UART. */
		UCTL0 = SWRST;

		/* Set pin function. */
    /* NOTE: this should have been done already in main::InitPorts()
     */
		P3SEL |= serTX_AND_RX;
    P3DIR |= BIT4;                                //enable TXD0 as output
    P3DIR &= ~BIT5;                               //enable RXD0 as input

		/* All other bits remain at zero for n, 8, 1 interrupt driven operation. 
		LOOPBACK MODE!*/
		UCTL0 |= CHAR | LISTEN;  // CHAR + LISTEN;
		UTCTL0 = SSEL0;

		/* Setup baud rate low byte. */
		U0BR0 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );

		/* Setup baud rate high byte. */
		ulBaudRateCount >>= 8UL;
		U0BR1 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );

    //no modulation
//    UMCTL0 = 0x00;                                

		/* Enable ports. */
		ME1 |= UTXE0 | URXE0;

		/* Set. */
		UCTL0 &= ~SWRST;

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

		/* Enable interrupts. */
		IE1 |= URXIE0 | UTXIE0;
	}
	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 portCHAR cSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
{
	/* Get the next character from the buffer.  Return false if no characters
	are available, or arrive before xBlockTime expires. */
	if( cQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
	{
		return ( signed portCHAR ) pdTRUE;
	}
	else
	{
		return ( signed portCHAR ) pdFALSE;
	}
}
/*-----------------------------------------------------------*/

signed portCHAR cSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
{
signed portCHAR cReturn;

	/* 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;
			U0TXBUF = cOutChar;
			cReturn = 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. */
			cReturn = cQueueSend( 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 ) && ( cReturn == ( signed portCHAR ) pdPASS ) )
      {
        portCHAR cOutChar;

        /* Get back the character we just posted. */
        cQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
        sTHREEmpty = pdFALSE;
        U0TXBUF = cOutChar;
      }
		}
	}
	portEXIT_CRITICAL();

	return ( signed portCHAR ) pdPASS;
}
/*-----------------------------------------------------------*/

/*
 * UART RX interrupt service routine.
 */
interrupt (UART0RX_VECTOR) vRxISR( void )
{
signed portCHAR cChar;

	/* Get the character from the UART and post it on the queue of Rxed 
	characters. */
	cChar = U0RXBUF;

	if( cQueueSendFromISR( xRxedChars, &cChar, pdFALSE ) )
	{
		/*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. */
//    vParTestToggleLED(6);   // *alz* flash that we get here
		taskYIELD(); // *alz* suspect that this is a problem?
	}
}
/*-----------------------------------------------------------*/

/*
 * UART Tx interrupt service routine.
 */
interrupt (UART0TX_VECTOR) vTxISR( void )
{
signed portCHAR cChar, cTaskWoken;

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

	if( cQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == ( signed portCHAR ) pdTRUE )
	{
		/* There was another character queued - transmit it now. */
		U0TXBUF = cChar;
	}
	else
	{
		/* There were no other characters to transmit. */
		sTHREEmpty = pdTRUE;
	}
}