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197 lines
8.0 KiB
C
197 lines
8.0 KiB
C
/*
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FreeRTOS V8.2.2 - Copyright (C) 2015 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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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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***************************************************************************
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>>! NOTE: The modification to the GPL is included to allow you to !<<
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>>! distribute a combined work that includes FreeRTOS without being !<<
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>>! obliged to provide the source code for proprietary components !<<
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>>! outside of the FreeRTOS kernel. !<<
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***************************************************************************
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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 on the following
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link: http://www.freertos.org/a00114.html
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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 is more than just the market leader, it *
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* is the industry's de facto standard. *
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* *
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* Help yourself get started quickly while simultaneously helping *
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* to support the FreeRTOS project by purchasing a FreeRTOS *
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* tutorial book, reference manual, or both: *
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* http://www.FreeRTOS.org/Documentation *
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* *
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***************************************************************************
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http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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the FAQ page "My application does not run, what could be wrong?". Have you
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defined configASSERT()?
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http://www.FreeRTOS.org/support - In return for receiving this top quality
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embedded software for free we request you assist our global community by
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participating in the support forum.
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http://www.FreeRTOS.org/training - Investing in training allows your team to
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be as productive as possible as early as possible. Now you can receive
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FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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Ltd, and the world's leading authority on the world's leading RTOS.
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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.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and commercial 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 USART0.
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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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#include "AT91R40008.h"
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#include "usart.h"
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/*-----------------------------------------------------------*/
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/* Constant to access the AIC. */
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#define serCLEAR_AIC_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 long ) (US_RXRDY | US_TXRDY | US_RXBRK | US_OVRE | US_FRAME | US_PARE) )
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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 QueueHandle_t xRxedChars;
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static QueueHandle_t xCharsForTx;
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/*-----------------------------------------------------------*/
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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_Wrapper( void ) __attribute__ ((naked));
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/* The ISR function that actually performs the work. This must be separate
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from the wrapper to ensure the correct stack frame is set up. */
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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, QueueHandle_t *pxRxedChars, QueueHandle_t *pxCharsForTx )
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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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}
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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 to ensure the
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stack frame is correctly set up. */
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__asm volatile( "bl vUART_ISR_Handler" );
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/* Restore the context of whichever task will 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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/* Now we can declare the local variables. These must be static. */
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signed char cChar;
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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unsigned long ulStatus;
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/* What caused the interrupt? */
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ulStatus = AT91C_BASE_US0->US_CSR & AT91C_BASE_US0->US_IMR;
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if (ulStatus & US_TXRDY)
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{
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/* The interrupt was caused by the THR becoming empty. Are there any
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more characters to transmit? */
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if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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{
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/* A character was retrieved from the queue so can be sent to the
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THR now. */
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AT91C_BASE_US0->US_THR = cChar;
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}
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else
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{
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/* Queue empty, nothing to send so turn off the Tx interrupt. */
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AT91C_BASE_US0->US_IDR = US_TXRDY;
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}
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}
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if (ulStatus & US_RXRDY)
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{
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/* The interrupt was caused by the receiver getting data. */
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cChar = AT91C_BASE_US0->US_RHR;
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xQueueSendFromISR(xRxedChars, &cChar, &xHigherPriorityTaskWoken);
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}
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/* Acknowledge the interrupt at AIC level... */
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AT91C_BASE_AIC->AIC_EOICR = serCLEAR_AIC_INTERRUPT;
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/* If an event caused a task to unblock then we call "Yield from ISR" to
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ensure that the unblocked task is the task that executes when the interrupt
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completes if the unblocked task has a priority higher than the interrupted
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task. */
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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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}
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/*-----------------------------------------------------------*/
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