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164 lines
5.8 KiB
C
164 lines
5.8 KiB
C
/*
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FreeRTOS.org V4.0.2 - Copyright (C) 2003-2006 Richard Barry.
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This file is part of the FreeRTOS.org distribution.
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FreeRTOS.org is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS.org is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS.org; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a combined work that includes FreeRTOS.org, without being obliged to provide
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the source code for any proprietary components. See the licensing section
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of http://www.FreeRTOS.org for full details of how and when the exception
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can be applied.
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***************************************************************************
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See http://www.FreeRTOS.org for documentation, latest information, license
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and contact details. Please ensure to read the configuration and relevant
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port sections of the online documentation.
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***************************************************************************
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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 portLONG ) 0 )
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/* Constants to determine the ISR source. */
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#define serSOURCE_THRE ( ( unsigned portCHAR ) 0x02 )
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#define serSOURCE_RX_TIMEOUT ( ( unsigned portCHAR ) 0x0c )
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#define serSOURCE_ERROR ( ( unsigned portCHAR ) 0x06 )
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#define serSOURCE_RX ( ( unsigned portCHAR ) 0x04 )
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#define serINTERRUPT_SOURCE_MASK ( ( unsigned portCHAR ) 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 portLONG 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, portLONG volatile **pplTHREEmptyFlag );
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/* UART0 interrupt service routine. This can cause a context switch so MUST
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be declared "naked". */
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void vUART_ISR( void ) __attribute__ ((naked));
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/*-----------------------------------------------------------*/
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void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars,
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xQueueHandle *pxCharsForTx, portLONG 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 portCHAR ) );
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xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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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 = ( portLONG ) pdTRUE;
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*pplTHREEmptyFlag = &lTHREEmpty;
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}
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/*-----------------------------------------------------------*/
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void vUART_ISR( void )
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{
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/* This ISR can cause a context switch, so the first statement must be a
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call to the portENTER_SWITCHING_ISR() macro. This must be BEFORE any
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variable declarations. */
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portENTER_SWITCHING_ISR();
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/* Now we can declare the local variables. */
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signed portCHAR cChar;
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portBASE_TYPE xTaskWokenByTx = pdFALSE, xTaskWokenByRx = 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, &xTaskWokenByTx ) == 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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if( xQueueSendFromISR( xRxedChars, &cChar, ( portBASE_TYPE ) pdFALSE ) )
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{
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xTaskWokenByRx = pdTRUE;
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}
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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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/* Clear the ISR in the VIC. */
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VICVectAddr = serCLEAR_VIC_INTERRUPT;
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/* Exit the ISR. If a task was woken by either a character being received
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or transmitted then a context switch will occur. */
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portEXIT_SWITCHING_ISR( ( xTaskWokenByTx || xTaskWokenByRx ) );
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}
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/*-----------------------------------------------------------*/
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