mirror of
https://github.com/FreeRTOS/FreeRTOS-Kernel.git
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274 lines
9.9 KiB
C
274 lines
9.9 KiB
C
/*
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FreeRTOS V8.0.0:rc1 - Copyright (C) 2014 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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***************************************************************************
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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 has become a de facto standard. *
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* *
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* Help yourself get started quickly and support the FreeRTOS *
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* project by purchasing a FreeRTOS tutorial book, reference *
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* manual, or both from: http://www.FreeRTOS.org/Documentation *
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* *
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* Thank you! *
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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 distribute
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>>! a combined work that includes FreeRTOS without being obliged to provide
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>>! the source code for proprietary components outside of the FreeRTOS
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>>! kernel.
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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 from the following
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link: http://www.freertos.org/a00114.html
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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, books, training, latest versions,
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license and Real Time Engineers Ltd. 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, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and 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 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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/* Library includes. */
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#include "usart/usart.h"
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#include "pmc/pmc.h"
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#include "irq/irq.h"
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#include "pio/pio.h"
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/*-----------------------------------------------------------*/
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/* Interrupt control macros. */
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#define serINTERRUPT_LEVEL ( 5 )
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#define vInterruptOn() BOARD_USART_BASE->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY )
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#define vInterruptOff() BOARD_USART_BASE->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 - called from the assembly entry point. */
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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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extern void ( vUART_ISR )( void );
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const Pin xUSART_Pins[] = { BOARD_PIN_USART_RXD, BOARD_PIN_USART_TXD };
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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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portENTER_CRITICAL();
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{
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/* Enable the peripheral clock in the PMC. */
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PMC_EnablePeripheral( BOARD_ID_USART );
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/* Configure the USART. */
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USART_Configure( BOARD_USART_BASE, AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE | AT91C_US_NBSTOP_1_BIT, ulWantedBaud, configCPU_CLOCK_HZ );
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/* Configure the interrupt. Note the pre-emption priority is set
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in bits [8:15] of the priority value passed as the parameter. */
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IRQ_ConfigureIT( BOARD_ID_USART, ( configMAX_SYSCALL_INTERRUPT_PRIORITY << 8 ), vSerialISR );
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IRQ_EnableIT( BOARD_ID_USART );
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/* Enable receiver & transmitter. */
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USART_SetTransmitterEnabled( BOARD_USART_BASE, pdTRUE );
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USART_SetReceiverEnabled( BOARD_USART_BASE, pdTRUE );
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/* Configure IO for USART use. */
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PIO_Configure( xUSART_Pins, PIO_LISTSIZE( xUSART_Pins ) );
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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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/* 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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}
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/*-----------------------------------------------------------*/
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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 = BOARD_USART_BASE->US_CSR &= BOARD_USART_BASE->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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BOARD_USART_BASE->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 = BOARD_USART_BASE->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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}
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