/* | |
FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd. | |
*************************************************************************** | |
* * | |
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* "Using the FreeRTOS Real Time Kernel - a Practical Guide" * | |
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*************************************************************************** | |
This file is part of the FreeRTOS distribution. | |
FreeRTOS is free software; you can redistribute it and/or modify it under | |
the terms of the GNU General Public License (version 2) as published by the | |
Free Software Foundation AND MODIFIED BY the FreeRTOS exception. | |
***NOTE*** The exception to the GPL is included to allow you to distribute | |
a combined work that includes FreeRTOS without being obliged to provide the | |
source code for proprietary components outside of the FreeRTOS kernel. | |
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT | |
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
more details. You should have received a copy of the GNU General Public | |
License and the FreeRTOS license exception along with FreeRTOS; if not it | |
can be viewed here: http://www.freertos.org/a00114.html and also obtained | |
by writing to Richard Barry, contact details for whom are available on the | |
FreeRTOS WEB site. | |
1 tab == 4 spaces! | |
http://www.FreeRTOS.org - Documentation, latest information, license and | |
contact details. | |
http://www.SafeRTOS.com - A version that is certified for use in safety | |
critical systems. | |
http://www.OpenRTOS.com - Commercial support, development, porting, | |
licensing and training services. | |
*/ | |
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. | |
NOTE: This driver is primarily to test the scheduler functionality. It does | |
not effectively use the buffers or DMA and is therefore not intended to be | |
an example of an efficient driver. */ | |
/* Standard include file. */ | |
#include <stdlib.h> | |
#include <plib.h> | |
/* Scheduler include files. */ | |
#include "FreeRTOS.h" | |
#include "queue.h" | |
#include "task.h" | |
/* Demo app include files. */ | |
#include "serial.h" | |
/* Hardware setup. */ | |
#define serSET_FLAG ( 1 ) | |
/* The queues used to communicate between tasks and ISR's. */ | |
static xQueueHandle xRxedChars; | |
static xQueueHandle xCharsForTx; | |
/* Flag used to indicate the tx status. */ | |
static portBASE_TYPE xTxHasEnded; | |
/*-----------------------------------------------------------*/ | |
/* The UART interrupt handler. As this uses the FreeRTOS assembly interrupt | |
entry point the IPL setting in the following prototype has no effect. The | |
interrupt priority is set by the call to ConfigIntUART2() in | |
xSerialPortInitMinimal(). */ | |
void __attribute__( (interrupt(ipl1), vector(_UART2_VECTOR))) vU2InterruptWrapper( void ); | |
/*-----------------------------------------------------------*/ | |
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
{ | |
unsigned portSHORT usBRG; | |
/* Create the queues used by the com test task. */ | |
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) ); | |
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) ); | |
/* Configure the UART and interrupts. */ | |
usBRG = (unsigned portSHORT)(( (float)configPERIPHERAL_CLOCK_HZ / ( (float)16 * (float)ulWantedBaud ) ) - (float)0.5); | |
OpenUART2( UART_EN, UART_RX_ENABLE | UART_TX_ENABLE | UART_INT_TX | UART_INT_RX_CHAR, usBRG ); | |
ConfigIntUART2( ( configKERNEL_INTERRUPT_PRIORITY + 1 ) | UART_INT_SUB_PR0 | UART_TX_INT_EN | UART_RX_INT_EN ); | |
xTxHasEnded = pdTRUE; | |
/* Only a single port is implemented so we don't need to return anything. */ | |
return NULL; | |
} | |
/*-----------------------------------------------------------*/ | |
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime ) | |
{ | |
/* Only one port is supported. */ | |
( void ) pxPort; | |
/* Get the next character from the buffer. Return false if no characters | |
are available or arrive before xBlockTime expires. */ | |
if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) ) | |
{ | |
return pdTRUE; | |
} | |
else | |
{ | |
return pdFALSE; | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime ) | |
{ | |
/* Only one port is supported. */ | |
( void ) pxPort; | |
/* Return false if after the block time there is no room on the Tx queue. */ | |
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS ) | |
{ | |
return pdFAIL; | |
} | |
/* A critical section should not be required as xTxHasEnded will not be | |
written to by the ISR if it is already 0 (is this correct?). */ | |
if( xTxHasEnded ) | |
{ | |
xTxHasEnded = pdFALSE; | |
IFS1bits.U2TXIF = serSET_FLAG; | |
} | |
return pdPASS; | |
} | |
/*-----------------------------------------------------------*/ | |
void vSerialClose( xComPortHandle xPort ) | |
{ | |
} | |
/*-----------------------------------------------------------*/ | |
void vU2InterruptHandler( void ) | |
{ | |
/* Declared static to minimise stack use. */ | |
static portCHAR cChar; | |
static portBASE_TYPE xHigherPriorityTaskWoken; | |
xHigherPriorityTaskWoken = pdFALSE; | |
/* Are any Rx interrupts pending? */ | |
if( mU2RXGetIntFlag() ) | |
{ | |
while( U2STAbits.URXDA ) | |
{ | |
/* Retrieve the received character and place it in the queue of | |
received characters. */ | |
cChar = U2RXREG; | |
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken ); | |
} | |
mU2RXClearIntFlag(); | |
} | |
/* Are any Tx interrupts pending? */ | |
if( mU2TXGetIntFlag() ) | |
{ | |
while( !( U2STAbits.UTXBF ) ) | |
{ | |
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE ) | |
{ | |
/* Send the next character queued for Tx. */ | |
U2TXREG = cChar; | |
} | |
else | |
{ | |
/* Queue empty, nothing to send. */ | |
xTxHasEnded = pdTRUE; | |
break; | |
} | |
} | |
mU2TXClearIntFlag(); | |
} | |
/* If sending or receiving necessitates a context switch, then switch now. */ | |
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken ); | |
} | |