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269 lines
9.6 KiB
C
269 lines
9.6 KiB
C
/*
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FreeRTOS V6.0.5 - Copyright (C) 2010 Real Time Engineers Ltd.
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***************************************************************************
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* *
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* If you are: *
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* *
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* + New to FreeRTOS, *
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* + Wanting to learn FreeRTOS or multitasking in general quickly *
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* + Looking for basic training, *
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* + Wanting to improve your FreeRTOS skills and productivity *
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* *
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* then take a look at the FreeRTOS eBook *
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* *
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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* http://www.FreeRTOS.org/Documentation *
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* *
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* A pdf reference manual is also available. Both are usually delivered *
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* to your inbox within 20 minutes to two hours when purchased between 8am *
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* and 8pm GMT (although please allow up to 24 hours in case of *
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* exceptional circumstances). 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 exception 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 the
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source code for proprietary components outside of the FreeRTOS kernel.
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FreeRTOS 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. 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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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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/*
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BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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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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/* Demo application includes. */
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#include "serial.h"
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/* Atmel library includes. */
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#include <usart/usart.h>
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#include <aic/aic.h>
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#include <pmc/pmc.h>
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/*-----------------------------------------------------------*/
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/* Location of the COM0 registers. */
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#define serCOM0 ( ( AT91PS_USART ) AT91C_BASE_US0 )
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/* Interrupt control macros. */
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#define serINTERRUPT_LEVEL ( 5 )
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#define vInterruptOn() serCOM0->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY )
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#define vInterruptOff() serCOM0->US_IDR = AT91C_US_TXRDY
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/* Misc constants. */
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#define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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#define serHANDLE ( ( xComPortHandle ) 1 )
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#define serNO_BLOCK ( ( portTickType ) 0 )
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#define serNO_TIMEGUARD ( ( unsigned long ) 0 )
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#define serNO_PERIPHERAL_B_SETUP ( ( unsigned long ) 0 )
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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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/*-----------------------------------------------------------*/
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/* The interrupt service routine. */
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__arm void vSerialISR( void );
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/*-----------------------------------------------------------*/
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/*
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* See the serial2.h header file.
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*/
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xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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{
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xComPortHandle xReturn = serHANDLE;
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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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/* If the queues were created correctly then setup the serial port
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hardware. */
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if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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{
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PMC_EnablePeripheral( AT91C_ID_US0 );
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portENTER_CRITICAL();
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{
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USART_Configure( serCOM0, ( AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE ), ulWantedBaud, configCPU_CLOCK_HZ );
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/* Enable Rx and Tx. */
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USART_SetTransmitterEnabled( serCOM0, pdTRUE );
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USART_SetReceiverEnabled( serCOM0, pdTRUE );
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/* Enable the Rx interrupts. The Tx interrupts are not enabled
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until there are characters to be transmitted. */
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serCOM0->US_IER = AT91C_US_RXRDY;
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/* Enable the interrupts in the AIC. */
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AIC_ConfigureIT( AT91C_ID_US0, AT91C_AIC_PRIOR_LOWEST, ( void (*)( void ) ) vSerialISR );
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AIC_EnableIT( AT91C_ID_US0 );
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}
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portEXIT_CRITICAL();
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}
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else
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{
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xReturn = ( xComPortHandle ) 0;
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}
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/* This demo file only supports a single port but we have to return
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something to comply with the standard demo header file. */
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return xReturn;
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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{
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/* The port handle is not required as this driver only supports one port. */
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( void ) pxPort;
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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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void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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{
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signed char *pxNext;
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/* A couple of parameters that this port does not use. */
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( void ) usStringLength;
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( void ) pxPort;
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/* NOTE: This implementation does not handle the queue being full as no
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block time is used! */
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/* The port handle is not required as this driver only supports UART0. */
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( void ) pxPort;
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/* Send each character in the string, one at a time. */
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pxNext = ( signed char * ) pcString;
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while( *pxNext )
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{
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xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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pxNext++;
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}
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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{
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/* Just to remove compiler warning. */
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( void ) pxPort;
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/* Place the character in the queue of characters to be transmitted. */
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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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/* 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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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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/* Not supported as not required by the demo application. */
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( void ) xPort;
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}
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/*-----------------------------------------------------------*/
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/* Serial port ISR. This can cause a context switch so is not defined as a
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standard ISR using the __irq keyword. Instead a wrapper function is defined
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within serialISR.s79 which in turn calls this function. See the port
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documentation on the FreeRTOS.org website for more information. */
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__arm void vSerialISR( void )
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{
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unsigned long ulStatus;
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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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ulStatus = serCOM0->US_CSR &= serCOM0->US_IMR;
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if( ulStatus & AT91C_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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serCOM0->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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vInterruptOff();
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}
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}
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if( ulStatus & AT91C_US_RXRDY )
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{
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/* The interrupt was caused by a character being received. Grab the
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character from the RHR and place it in the queue or received
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characters. */
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cChar = serCOM0->US_RHR;
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xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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}
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/* If a task was woken by either a character being received or a character
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being transmitted then we may need to switch to another task. */
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portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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/* End the interrupt in the AIC. */
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AT91C_BASE_AIC->AIC_EOICR = 0;
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}
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