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264 lines
8.9 KiB
C
264 lines
8.9 KiB
C
/*
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FreeRTOS.org V4.4.0 - Copyright (C) 2003-2007 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
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FreeRTOS.org is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FreeRTOS.org; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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A special exception to the GPL can be applied should you wish to distribute
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a 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 of how and when the exception
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can be applied.
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***************************************************************************
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See http://www.FreeRTOS.org for documentation, latest information, license
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and contact details. Please ensure to read the configuration and relevant
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port sections of the online documentation.
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Also see http://www.SafeRTOS.com for an IEC 61508 compliant version along
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with commercial development and support options.
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***************************************************************************
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*/
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/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER for port 1.
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Note that this driver is written to test the RTOS port and is not intended
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to represent an optimised solution. In particular no use is made of the DMA
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peripheral. */
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/* Standard include files. */
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#include <stdlib.h>
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/* Scheduler include files. */
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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 include files. */
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#include "serial.h"
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/* The queues used to communicate between the task code and the interrupt
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service routines. */
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static xQueueHandle xRxedChars;
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static xQueueHandle xCharsForTx;
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/* Hardware specific constants. */
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#define serTX_INTERRUPT ( ( unsigned portCHAR ) 0x80 )
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#define serRX_INTERRUPT ( ( unsigned portCHAR ) 0x40 )
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#define serTX_ENABLE ( ( unsigned portCHAR ) 0x20 )
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#define serRX_ENABLE ( ( unsigned portCHAR ) 0x10 )
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/* Macros to turn on and off the serial port THRE interrupt while leaving the
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other register bits in their correct state. The Rx interrupt is always
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enabled. */
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#define serTX_INTERRUPT_ON() SCR1 = serTX_INTERRUPT | serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE;
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#define serTX_INTERRUPT_OFF() SCR1 = serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE;
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/* Bit used to switch on the channel 1 serial port in the module stop
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register. */
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#define serMSTP6 ( ( unsigned portSHORT ) 0x0040 )
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/* Interrupt service routines. Note that the Rx and Tx service routines can
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cause a context switch and are therefore defined with the saveall attribute in
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addition to the interrupt_handler attribute. See the FreeRTOS.org WEB site
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documentation for a full explanation.*/
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void vCOM_1_Rx_ISR( void ) __attribute__ ( ( saveall, interrupt_handler ) );
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void vCOM_1_Tx_ISR( void ) __attribute__ ( ( saveall, interrupt_handler ) );
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void vCOM_1_Error_ISR( void ) __attribute__ ( ( interrupt_handler ) );
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/*-----------------------------------------------------------*/
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/*
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* Initialise port 1 for interrupt driven communications.
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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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/* Create the queues used to communicate between the tasks and the
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interrupt service routines. */
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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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/* No parity, 8 data bits and 1 stop bit is the default so does not require
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configuration - setup the remains of the hardware. */
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portENTER_CRITICAL();
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{
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/* Turn channel 1 on. */
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MSTPCR &= ~serMSTP6;
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/* Enable the channels and the Rx interrupt. The Tx interrupt is only
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enabled when data is being transmitted. */
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SCR1 = serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE;
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/* Bit rate settings for 22.1184MHz clock only!. */
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switch( ulWantedBaud )
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{
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case 4800 : BRR1 = 143;
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break;
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case 9600 : BRR1 = 71;
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break;
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case 19200 : BRR1 = 35;
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break;
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case 38400 : BRR1 = 17;
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break;
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case 57600 : BRR1 = 11;
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break;
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case 115200 : BRR1 = 5;
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break;
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default : BRR1 = 5;
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break;
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}
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}
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portEXIT_CRITICAL();
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/* Unlike some ports, this driver 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 queue. 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 = pdPASS;
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/* Return false if after the block time there is no room on the Tx queue. */
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portENTER_CRITICAL();
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{
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/* Send a character to the queue of characters waiting transmission.
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The queue is serviced by the Tx ISR. */
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if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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{
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/* Could not post onto the queue. */
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xReturn = pdFAIL;
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}
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else
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{
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/* The message was posted onto the queue so we turn on the Tx
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interrupt to allow the Tx ISR to remove the character from the
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queue. */
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serTX_INTERRUPT_ON();
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}
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}
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portEXIT_CRITICAL();
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return xReturn;
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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. */
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( void ) xPort;
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}
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/*-----------------------------------------------------------*/
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void vCOM_1_Rx_ISR( void )
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{
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/* This can cause a context switch so this macro must be the first line
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in the function. */
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portENTER_SWITCHING_ISR();
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/* As this is a switching ISR the local variables must be declared as
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static. */
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static portCHAR cRxByte;
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static portBASE_TYPE xTaskWokenByPost;
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/* Get the character. */
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cRxByte = RDR1;
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/* Post the character onto the queue of received characters - noting
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whether or not this wakes a task. */
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xTaskWokenByPost = xQueueSendFromISR( xRxedChars, &cRxByte, pdFALSE );
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/* Clear the interrupt. */
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SSR1 &= ~serRX_INTERRUPT;
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/* This must be the last line in the function. We pass cTaskWokenByPost so
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a context switch will occur if the received character woke a task that has
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a priority higher than the task we interrupted. */
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portEXIT_SWITCHING_ISR( xTaskWokenByPost );
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}
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/*-----------------------------------------------------------*/
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void vCOM_1_Tx_ISR( void )
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{
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/* This can cause a context switch so this macro must be the first line
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in the function. */
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portENTER_SWITCHING_ISR();
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/* As this is a switching ISR the local variables must be declared as
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static. */
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static portCHAR cTxByte;
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static signed portBASE_TYPE xTaskWokenByTx;
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/* This variable is static so must be explicitly reinitialised each
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time the function executes. */
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xTaskWokenByTx = pdFALSE;
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/* The interrupt was caused by the THR becoming empty. Are there any
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more characters to transmit? Note whether or not the Tx interrupt has
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woken a task. */
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if( xQueueReceiveFromISR( xCharsForTx, &cTxByte, &xTaskWokenByTx ) == 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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TDR1 = cTxByte;
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/* Clear the interrupt. */
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SSR1 &= ~serTX_INTERRUPT;
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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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serTX_INTERRUPT_OFF();
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}
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/* This must be the last line in the function. We pass cTaskWokenByTx so
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a context switch will occur if the Tx'ed character woke a task that has
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a priority higher than the task we interrupted. */
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portEXIT_SWITCHING_ISR( xTaskWokenByTx );
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}
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/*-----------------------------------------------------------*/
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/*
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* This ISR cannot cause a context switch so requires no special
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* considerations.
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*/
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void vCOM_1_Error_ISR( void )
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{
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volatile unsigned portCHAR ucIn;
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ucIn = SSR1;
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SSR1 = 0;
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}
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