/* | |
FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd. | |
*************************************************************************** | |
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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 | |
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License and the FreeRTOS license exception along with FreeRTOS; if not it | |
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*/ | |
/* | |
BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0. | |
This file contains all the serial port components that must be compiled | |
to ARM mode. The components that can be compiled to either ARM or THUMB | |
mode are contained in serial.c. | |
*/ | |
/* Standard includes. */ | |
#include <stdlib.h> | |
/* Scheduler includes. */ | |
#include "FreeRTOS.h" | |
#include "queue.h" | |
#include "task.h" | |
/* Demo application includes. */ | |
#include "serial.h" | |
/*-----------------------------------------------------------*/ | |
/* Constant to access the VIC. */ | |
#define serCLEAR_VIC_INTERRUPT ( ( unsigned long ) 0 ) | |
/* Constants to determine the ISR source. */ | |
#define serSOURCE_THRE ( ( unsigned char ) 0x02 ) | |
#define serSOURCE_RX_TIMEOUT ( ( unsigned char ) 0x0c ) | |
#define serSOURCE_ERROR ( ( unsigned char ) 0x06 ) | |
#define serSOURCE_RX ( ( unsigned char ) 0x04 ) | |
#define serINTERRUPT_SOURCE_MASK ( ( unsigned char ) 0x0f ) | |
/* Queues used to hold received characters, and characters waiting to be | |
transmitted. */ | |
static xQueueHandle xRxedChars; | |
static xQueueHandle xCharsForTx; | |
static volatile long lTHREEmpty; | |
/*-----------------------------------------------------------*/ | |
/* | |
* The queues are created in serialISR.c as they are used from the ISR. | |
* Obtain references to the queues and THRE Empty flag. | |
*/ | |
void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag ); | |
/* UART0 interrupt service routine entry point. */ | |
void vUART_ISR_Wrapper( void ) __attribute__ ((naked)); | |
/* UART0 interrupt service routine handler. */ | |
void vUART_ISR_Handler( void ) __attribute__ ((noinline)); | |
/*-----------------------------------------------------------*/ | |
void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, | |
xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag ) | |
{ | |
/* Create the queues used to hold Rx and Tx characters. */ | |
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); | |
xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); | |
/* Pass back a reference to the queues so the serial API file can | |
post/receive characters. */ | |
*pxRxedChars = xRxedChars; | |
*pxCharsForTx = xCharsForTx; | |
/* Initialise the THRE empty flag - and pass back a reference. */ | |
lTHREEmpty = ( long ) pdTRUE; | |
*pplTHREEmptyFlag = &lTHREEmpty; | |
} | |
/*-----------------------------------------------------------*/ | |
void vUART_ISR_Wrapper( void ) | |
{ | |
/* Save the context of the interrupted task. */ | |
portSAVE_CONTEXT(); | |
/* Call the handler. This must be a separate function from the wrapper | |
to ensure the correct stack frame is set up. */ | |
__asm volatile ("bl vUART_ISR_Handler"); | |
/* Restore the context of whichever task is going to run next. */ | |
portRESTORE_CONTEXT(); | |
} | |
/*-----------------------------------------------------------*/ | |
void vUART_ISR_Handler( void ) | |
{ | |
signed char cChar; | |
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; | |
/* What caused the interrupt? */ | |
switch( UART0_IIR & serINTERRUPT_SOURCE_MASK ) | |
{ | |
case serSOURCE_ERROR : /* Not handling this, but clear the interrupt. */ | |
cChar = UART0_LSR; | |
break; | |
case serSOURCE_THRE : /* The THRE is empty. If there is another | |
character in the Tx queue, send it now. */ | |
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE ) | |
{ | |
UART0_THR = cChar; | |
} | |
else | |
{ | |
/* There are no further characters | |
queued to send so we can indicate | |
that the THRE is available. */ | |
lTHREEmpty = pdTRUE; | |
} | |
break; | |
case serSOURCE_RX_TIMEOUT : | |
case serSOURCE_RX : /* A character was received. Place it in | |
the queue of received characters. */ | |
cChar = UART0_RBR; | |
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken ); | |
break; | |
default : /* There is nothing to do, leave the ISR. */ | |
break; | |
} | |
if( xHigherPriorityTaskWoken ) | |
{ | |
portYIELD_FROM_ISR(); | |
} | |
/* Clear the ISR in the VIC. */ | |
VICVectAddr = serCLEAR_VIC_INTERRUPT; | |
} | |