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205 lines
7.8 KiB
C
205 lines
7.8 KiB
C
/*
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FreeRTOS V8.0.0:rc1 - Copyright (C) 2014 Real Time Engineers Ltd.
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All rights reserved
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VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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***************************************************************************
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* *
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* FreeRTOS provides completely free yet professionally developed, *
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* robust, strictly quality controlled, supported, and cross *
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* platform software that has become a de facto standard. *
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* *
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* Help yourself get started quickly and support the FreeRTOS *
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* project by purchasing a FreeRTOS tutorial book, reference *
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* manual, or both from: http://www.FreeRTOS.org/Documentation *
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* *
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* Thank you! *
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* *
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***************************************************************************
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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>>! NOTE: The modification to the GPL is included to allow you to distribute
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>>! a combined work that includes FreeRTOS without being obliged to provide
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>>! the source code for proprietary components outside of the FreeRTOS
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>>! kernel.
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. Full license text is available from the following
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link: http://www.freertos.org/a00114.html
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1 tab == 4 spaces!
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***************************************************************************
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* *
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* Having a problem? Start by reading the FAQ "My application does *
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* not run, what could be wrong?" *
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* *
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* http://www.FreeRTOS.org/FAQHelp.html *
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* *
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***************************************************************************
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http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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license and Real Time Engineers Ltd. contact details.
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http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and middleware.
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http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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engineered and independently SIL3 certified version for use in safety and
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mission critical applications that require provable dependability.
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1 tab == 4 spaces!
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*/
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/*
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BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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This file contains all the serial port components that must be compiled
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to ARM mode. The components that can be compiled to either ARM or THUMB
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mode are contained in serial.c.
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*/
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/* Standard includes. */
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#include <stdlib.h>
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/* Scheduler includes. */
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#include "FreeRTOS.h"
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#include "queue.h"
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#include "task.h"
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/* Demo application includes. */
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#include "serial.h"
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/*-----------------------------------------------------------*/
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/* Constant to access the VIC. */
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#define serCLEAR_VIC_INTERRUPT ( ( unsigned long ) 0 )
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/* Constants to determine the ISR source. */
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#define serSOURCE_THRE ( ( unsigned char ) 0x02 )
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#define serSOURCE_RX_TIMEOUT ( ( unsigned char ) 0x0c )
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#define serSOURCE_ERROR ( ( unsigned char ) 0x06 )
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#define serSOURCE_RX ( ( unsigned char ) 0x04 )
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#define serINTERRUPT_SOURCE_MASK ( ( unsigned char ) 0x0f )
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/* Queues used to hold received characters, and characters waiting to be
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transmitted. */
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static xQueueHandle xRxedChars;
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static xQueueHandle xCharsForTx;
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static volatile long lTHREEmpty;
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/*-----------------------------------------------------------*/
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/*
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* The queues are created in serialISR.c as they are used from the ISR.
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* Obtain references to the queues and THRE Empty flag.
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*/
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void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag );
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/* UART0 interrupt service routine entry point. */
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void vUART_ISR_Wrapper( void ) __attribute__ ((naked));
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/* UART0 interrupt service routine handler. */
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void vUART_ISR_Handler( void ) __attribute__ ((noinline));
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/*-----------------------------------------------------------*/
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void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars,
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xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag )
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{
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/* Create the queues used to hold Rx and Tx characters. */
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xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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/* Pass back a reference to the queues so the serial API file can
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post/receive characters. */
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*pxRxedChars = xRxedChars;
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*pxCharsForTx = xCharsForTx;
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/* Initialise the THRE empty flag - and pass back a reference. */
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lTHREEmpty = ( long ) pdTRUE;
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*pplTHREEmptyFlag = &lTHREEmpty;
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}
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/*-----------------------------------------------------------*/
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void vUART_ISR_Wrapper( void )
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{
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/* Save the context of the interrupted task. */
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portSAVE_CONTEXT();
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/* Call the handler. This must be a separate function from the wrapper
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to ensure the correct stack frame is set up. */
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__asm volatile ("bl vUART_ISR_Handler");
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/* Restore the context of whichever task is going to run next. */
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portRESTORE_CONTEXT();
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}
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/*-----------------------------------------------------------*/
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void vUART_ISR_Handler( void )
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{
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signed char cChar;
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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/* What caused the interrupt? */
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switch( UART0_IIR & serINTERRUPT_SOURCE_MASK )
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{
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case serSOURCE_ERROR : /* Not handling this, but clear the interrupt. */
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cChar = UART0_LSR;
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break;
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case serSOURCE_THRE : /* The THRE is empty. If there is another
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character in the Tx queue, send it now. */
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if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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{
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UART0_THR = cChar;
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}
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else
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{
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/* There are no further characters
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queued to send so we can indicate
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that the THRE is available. */
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lTHREEmpty = pdTRUE;
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}
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break;
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case serSOURCE_RX_TIMEOUT :
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case serSOURCE_RX : /* A character was received. Place it in
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the queue of received characters. */
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cChar = UART0_RBR;
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xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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break;
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default : /* There is nothing to do, leave the ISR. */
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break;
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}
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if( xHigherPriorityTaskWoken )
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{
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portYIELD_FROM_ISR();
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}
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/* Clear the ISR in the VIC. */
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VICVectAddr = serCLEAR_VIC_INTERRUPT;
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}
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