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240 lines
8.6 KiB
C
240 lines
8.6 KiB
C
/*
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FreeRTOS V7.2.0 - Copyright (C) 2012 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* FreeRTOS tutorial books are available in pdf and paperback. *
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* Complete, revised, and edited pdf reference manuals are also *
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* available. *
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* *
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* Purchasing FreeRTOS documentation will not only help you, by *
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* ensuring you get running as quickly as possible and with an *
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* in-depth knowledge of how to use FreeRTOS, it will also help *
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* the FreeRTOS project to continue with its mission of providing *
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* professional grade, cross platform, de facto standard solutions *
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* for microcontrollers - completely free of charge! *
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* *
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* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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* *
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* Thank you for using FreeRTOS, and thank you for your support! *
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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
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distribute a combined work that includes FreeRTOS without being obliged to
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provide the source code for proprietary components outside of the FreeRTOS
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kernel. FreeRTOS is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details. You should have received a copy of the GNU General Public
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License and the FreeRTOS license exception along with FreeRTOS; if not it
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can be viewed here: http://www.freertos.org/a00114.html and also obtained
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by writing to Richard Barry, contact details for whom are available on the
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FreeRTOS WEB site.
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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, training, latest information,
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license and 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.
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Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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the code with commercial support, indemnification, and middleware, under
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the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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provide a safety engineered and independently SIL3 certified version under
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the SafeRTOS brand: http://www.SafeRTOS.com.
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*/
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/*
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* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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*
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* This file only supports UART 2
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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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/* The queue used to hold received characters. */
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static xQueueHandle xRxedChars;
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/* The queue used to hold characters waiting transmission. */
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static xQueueHandle xCharsForTx;
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static volatile portSHORT sTHREEmpty;
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/*-----------------------------------------------------------*/
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xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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{
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portENTER_CRITICAL();
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{
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/* Create the queues used by the com test task. */
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xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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/* Initialize UART asynchronous mode */
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BGR02 = configPER_CLOCK_HZ / ulWantedBaud;
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SCR02 = 0x17; /* 8N1 */
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SMR02 = 0x0d; /* enable SOT3, Reset, normal mode */
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SSR02 = 0x02; /* LSB first, enable receive interrupts */
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PFR20_D0 = 1; /* enable UART */
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PFR20_D1 = 1; /* enable UART */
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EPFR20_D1 = 0; /* enable UART */
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}
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portEXIT_CRITICAL();
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/* Unlike other ports, this serial code does not allow for more than one
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com port. We therefore don't return a pointer to a port structure and can
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instead just return NULL. */
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return NULL;
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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{
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/* Get the next character from the buffer. Return false if no characters
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are available, or arrive before xBlockTime expires. */
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if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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{
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return pdTRUE;
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}
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else
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{
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return pdFALSE;
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}
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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{
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signed portBASE_TYPE xReturn;
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/* Transmit a character. */
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portENTER_CRITICAL();
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{
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if( sTHREEmpty == pdTRUE )
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{
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/* If sTHREEmpty is true then the UART Tx ISR has indicated that
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there are no characters queued to be transmitted - so we can
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write the character directly to the shift Tx register. */
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sTHREEmpty = pdFALSE;
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TDR02 = cOutChar;
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xReturn = pdPASS;
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}
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else
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{
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/* sTHREEmpty is false, so there are still characters waiting to be
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transmitted. We have to queue this character so it gets
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transmitted in turn. */
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/* Return false if after the block time there is no room on the Tx
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queue. It is ok to block inside a critical section as each task
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maintains it's own critical section status. */
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if (xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdTRUE)
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{
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xReturn = pdPASS;
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}
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else
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{
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xReturn = pdFAIL;
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}
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}
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if (pdPASS == xReturn)
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{
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/* Turn on the Tx interrupt so the ISR will remove the character from the
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queue and send it. This does not need to be in a critical section as
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if the interrupt has already removed the character the next interrupt
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will simply turn off the Tx interrupt again. */
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SSR02_TIE = 1;
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}
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}
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portEXIT_CRITICAL();
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return pdPASS;
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}
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/*-----------------------------------------------------------*/
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/*
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* UART RX interrupt service routine.
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*/
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__interrupt void UART2_RxISR (void)
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{
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signed portCHAR cChar;
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portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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/* Get the character from the UART and post it on the queue of Rxed
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characters. */
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cChar = RDR02;
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xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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if( xHigherPriorityTaskWoken )
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{
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/*If the post causes a task to wake force a context switch
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as the woken task may have a higher priority than the task we have
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interrupted. */
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portYIELD_FROM_ISR();
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}
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}
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/*-----------------------------------------------------------*/
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/*
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* UART Tx interrupt service routine.
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*/
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__interrupt void UART2_TxISR (void)
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{
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signed portCHAR cChar;
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signed portBASE_TYPE xTaskWoken = pdFALSE;
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/* The previous character has been transmitted. See if there are any
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further characters waiting transmission. */
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if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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{
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/* There was another character queued - transmit it now. */
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TDR02 = cChar;
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}
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else
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{
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/* There were no other characters to transmit. */
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sTHREEmpty = pdTRUE;
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/* Disable transmit interrupts */
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SSR02_TIE = 0;
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}
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}
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