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/*
FreeRTOS V8.0.0:rc1 - Copyright (C) 2014 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that has become a de facto standard. *
* *
* Help yourself get started quickly and support the FreeRTOS *
* project by purchasing a FreeRTOS tutorial book, reference *
* manual, or both from: http://www.FreeRTOS.org/Documentation *
* *
* Thank you! *
* *
***************************************************************************
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. Full license text is available from the following
link: http://www.freertos.org/a00114.html
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, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and middleware.
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.
1 tab == 4 spaces!
*/
/*
BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
This file contains all the serial port components that must be compiled
to ARM mode. The components that can be compiled to either ARM or THUMB
mode are contained in serial.c.
*/
/* Standard includes. */
#include <stdlib.h>
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
/* Demo application includes. */
#include "serial.h"
/*-----------------------------------------------------------*/
/* Constant to access the VIC. */
#define serCLEAR_VIC_INTERRUPT ( ( unsigned long ) 0 )
/* Constants to determine the ISR source. */
#define serSOURCE_THRE ( ( unsigned char ) 0x02 )
#define serSOURCE_RX_TIMEOUT ( ( unsigned char ) 0x0c )
#define serSOURCE_ERROR ( ( unsigned char ) 0x06 )
#define serSOURCE_RX ( ( unsigned char ) 0x04 )
#define serINTERRUPT_SOURCE_MASK ( ( unsigned char ) 0x0f )
/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static xQueueHandle xRxedChars;
static xQueueHandle xCharsForTx;
static volatile long lTHREEmpty;
/*-----------------------------------------------------------*/
/*
* The queues are created in serialISR.c as they are used from the ISR.
* Obtain references to the queues and THRE Empty flag.
*/
void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag );
/* UART0 interrupt service routine entry point. */
void vUART_ISR_Wrapper( void ) __attribute__ ((naked));
/* UART0 interrupt service routine handler. */
void vUART_ISR_Handler( void ) __attribute__ ((noinline));
/*-----------------------------------------------------------*/
void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars,
xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag )
{
/* Create the queues used to hold Rx and Tx characters. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
/* Pass back a reference to the queues so the serial API file can
post/receive characters. */
*pxRxedChars = xRxedChars;
*pxCharsForTx = xCharsForTx;
/* Initialise the THRE empty flag - and pass back a reference. */
lTHREEmpty = ( long ) pdTRUE;
*pplTHREEmptyFlag = &lTHREEmpty;
}
/*-----------------------------------------------------------*/
void vUART_ISR_Wrapper( void )
{
/* Save the context of the interrupted task. */
portSAVE_CONTEXT();
/* Call the handler. This must be a separate function from the wrapper
to ensure the correct stack frame is set up. */
__asm volatile ("bl vUART_ISR_Handler");
/* Restore the context of whichever task is going to run next. */
portRESTORE_CONTEXT();
}
/*-----------------------------------------------------------*/
void vUART_ISR_Handler( void )
{
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* What caused the interrupt? */
switch( UART0_IIR & serINTERRUPT_SOURCE_MASK )
{
case serSOURCE_ERROR : /* Not handling this, but clear the interrupt. */
cChar = UART0_LSR;
break;
case serSOURCE_THRE : /* The THRE is empty. If there is another
character in the Tx queue, send it now. */
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
{
UART0_THR = cChar;
}
else
{
/* There are no further characters
queued to send so we can indicate
that the THRE is available. */
lTHREEmpty = pdTRUE;
}
break;
case serSOURCE_RX_TIMEOUT :
case serSOURCE_RX : /* A character was received. Place it in
the queue of received characters. */
cChar = UART0_RBR;
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
break;
default : /* There is nothing to do, leave the ISR. */
break;
}
if( xHigherPriorityTaskWoken )
{
portYIELD_FROM_ISR();
}
/* Clear the ISR in the VIC. */
VICVectAddr = serCLEAR_VIC_INTERRUPT;
}
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