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217 lines
7.2 KiB
C
217 lines
7.2 KiB
C
/*
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FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 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 it
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under the terms of the GNU General Public License (version 2) as published
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by the Free Software Foundation and modified by the FreeRTOS exception.
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FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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You should have received a copy of the GNU General Public License along
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with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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A special exception to the GPL is included to allow you to distribute a
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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.
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***************************************************************************
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* *
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* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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* *
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* This is a concise, step by step, 'hands on' guide that describes both *
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* general multitasking concepts and FreeRTOS specifics. It presents and *
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* explains numerous examples that are written using the FreeRTOS API. *
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* Full source code for all the examples is provided in an accompanying *
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* .zip file. *
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* *
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***************************************************************************
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1 tab == 4 spaces!
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Please ensure to read the configuration and relevant port sections of the
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online documentation.
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http://www.FreeRTOS.org - Documentation, latest information, license and
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contact details.
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http://www.SafeRTOS.com - A version that is certified for use in safety
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critical systems.
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http://www.OpenRTOS.com - Commercial support, development, porting,
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licensing and training services.
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*/
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/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR IAR AVR PORT. */
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#include <stdlib.h>
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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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#include "serial.h"
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#define serBAUD_DIV_CONSTANT ( ( unsigned portLONG ) 16 )
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/* Constants for writing to UCSRB. */
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#define serRX_INT_ENABLE ( ( unsigned portCHAR ) 0x80 )
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#define serRX_ENABLE ( ( unsigned portCHAR ) 0x10 )
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#define serTX_ENABLE ( ( unsigned portCHAR ) 0x08 )
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#define serTX_INT_ENABLE ( ( unsigned portCHAR ) 0x20 )
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/* Constants for writing to UCSRC. */
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#define serUCSRC_SELECT ( ( unsigned portCHAR ) 0x80 )
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#define serEIGHT_DATA_BITS ( ( unsigned portCHAR ) 0x06 )
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static xQueueHandle xRxedChars;
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static xQueueHandle xCharsForTx;
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#define vInterruptOn() \
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{ \
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unsigned portCHAR ucByte; \
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\
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ucByte = UCSRB; \
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ucByte |= serTX_INT_ENABLE; \
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outb( UCSRB, ucByte ); \
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}
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/*-----------------------------------------------------------*/
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#define vInterruptOff() \
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{ \
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unsigned portCHAR ucByte; \
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\
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ucByte = UCSRB; \
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ucByte &= ~serTX_INT_ENABLE; \
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outb( UCSRB, ucByte ); \
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}
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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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unsigned portLONG ulBaudRateCounter;
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unsigned portCHAR ucByte;
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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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/* Calculate the baud rate register value from the equation in the
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data sheet. */
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ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned portLONG ) 1;
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/* Set the baud rate. */
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ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
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outb( UBRRL, ucByte );
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ulBaudRateCounter >>= ( unsigned portLONG ) 8;
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ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
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outb( UBRRH, ucByte );
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/* Enable the Rx interrupt. The Tx interrupt will get enabled
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later. Also enable the Rx and Tx. */
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outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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/* Set the data bits to 8. */
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outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS );
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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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/* Return false if after the block time there is no room on the Tx queue. */
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if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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{
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return pdFAIL;
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}
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vInterruptOn();
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return pdPASS;
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}
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/*-----------------------------------------------------------*/
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void vSerialClose( xComPortHandle xPort )
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{
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unsigned portCHAR ucByte;
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/* Turn off the interrupts. We may also want to delete the queues and/or
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re-install the original ISR. */
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portENTER_CRITICAL();
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{
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vInterruptOff();
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ucByte = UCSRB;
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ucByte &= ~serRX_INT_ENABLE;
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outb( UCSRB, ucByte );
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}
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portEXIT_CRITICAL();
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}
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/*-----------------------------------------------------------*/
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__interrupt void SIG_UART_RECV( void )
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{
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signed portCHAR ucChar, xHigherPriorityTaskWoken = pdFALSE;
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/* Get the character and post it on the queue of Rxed characters.
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If the post causes a task to wake force a context switch as the woken task
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may have a higher priority than the task we have interrupted. */
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ucChar = UDR;
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xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
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if( xHigherPriorityTaskWoken != pdFALSE )
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{
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taskYIELD();
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}
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}
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/*-----------------------------------------------------------*/
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__interrupt void SIG_UART_DATA( void )
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{
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signed portCHAR cChar, cTaskWoken = pdFALSE;
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if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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{
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/* Send the next character queued for Tx. */
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outb( UDR, cChar );
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}
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else
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{
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/* Queue empty, nothing to send. */
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vInterruptOff();
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}
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}
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