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/*
FreeRTOS V7.1.1 - Copyright (C) 2012 Real Time Engineers Ltd.
***************************************************************************
* *
* FreeRTOS tutorial books are available in pdf and paperback. *
* Complete, revised, and edited pdf reference manuals are also *
* available. *
* *
* Purchasing FreeRTOS documentation will not only help you, by *
* ensuring you get running as quickly as possible and with an *
* in-depth knowledge of how to use FreeRTOS, it will also help *
* the FreeRTOS project to continue with its mission of providing *
* professional grade, cross platform, de facto standard solutions *
* for microcontrollers - completely free of charge! *
* *
* >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
* *
* Thank you for using FreeRTOS, and thank you for your support! *
* *
***************************************************************************
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 modification 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!
***************************************************************************
* *
* Having a problem? Start by reading the FAQ "My application does *
* not run, what could be wrong? *
* *
* http://www.FreeRTOS.org/FAQHelp.html *
* *
***************************************************************************
http://www.FreeRTOS.org - Documentation, training, latest information,
license and contact details.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool.
Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
the code with commercial support, indemnification, and middleware, under
the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
provide a safety engineered and independently SIL3 certified version under
the SafeRTOS brand: http://www.SafeRTOS.com.
*/
/*
BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART
*/
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
/* Demo application includes. */
#include "serial.h"
/* Library includes. */
#include "xparameters.h"
#include "xuartlite.h"
#include "xuartlite_l.h"
/*-----------------------------------------------------------*/
/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static xQueueHandle xRxedChars;
static xQueueHandle xCharsForTx;
/* Structure that maintains information on the UART being used. */
static XUartLite xUART;
/*
* Sample UART interrupt handler. Note this is used to demonstrate the kernel
* features and test the port - it is not intended to represent an efficient
* implementation.
*/
static void vSerialISR( XUartLite *pxUART );
/*-----------------------------------------------------------*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
/* NOTE: The baud rate used by this driver is determined by the hardware
parameterization of the UART Lite peripheral, and the baud value passed to
this function has no effect. */
( void ) ulWantedBaud;
/* 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 ) );
/* Only initialise the UART if the queues were created correctly. */
if( ( xRxedChars != NULL ) && ( xCharsForTx != NULL ) )
{
XUartLite_Initialize( &xUART, XPAR_RS232_UART_1_DEVICE_ID );
XUartLite_ResetFifos( &xUART );
XUartLite_DisableInterrupt( &xUART );
if( xPortInstallInterruptHandler( XPAR_XPS_INTC_0_RS232_UART_1_INTERRUPT_INTR, ( XInterruptHandler )vSerialISR, (void *)&xUART ) == pdPASS )
{
/* xPortInstallInterruptHandler() could fail if
vPortSetupInterruptController() has not been called prior to this
function. */
XUartLite_EnableInterrupt( &xUART );
}
}
/* There is only one port so the handle is not used. */
return ( xComPortHandle ) 0;
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
{
/* The port handle is not required as this driver only supports one UART. */
( 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 char cOutChar, portTickType xBlockTime )
{
portBASE_TYPE xReturn = pdTRUE;
/* Just to remove compiler warning. */
( void ) pxPort;
portENTER_CRITICAL();
{
/* If the UART FIFO is full we can block posting the new data on the
Tx queue. */
if( XUartLite_mIsTransmitFull( XPAR_RS232_UART_1_BASEADDR ) )
{
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
{
xReturn = pdFAIL;
}
}
/* Otherwise, if there is data already in the queue we should add the
new data to the back of the queue to ensure the sequencing is
maintained. */
else if( uxQueueMessagesWaiting( xCharsForTx ) )
{
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
{
xReturn = pdFAIL;
}
}
/* If the UART FIFO is not full and there is no data already in the
queue we can write directly to the FIFO without disrupting the
sequence. */
else
{
XIo_Out32( XPAR_RS232_UART_1_BASEADDR + XUL_TX_FIFO_OFFSET, cOutChar );
}
}
portEXIT_CRITICAL();
return xReturn;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not supported as not required by the demo application. */
( void ) xPort;
}
/*-----------------------------------------------------------*/
static void vSerialISR( XUartLite *pxUART )
{
unsigned long ulISRStatus;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE, lDidSomething;
char cChar;
/* Just to remove compiler warning. */
( void ) pxUART;
do
{
lDidSomething = pdFALSE;
ulISRStatus = XIo_In32( XPAR_RS232_UART_1_BASEADDR + XUL_STATUS_REG_OFFSET );
if( ( ulISRStatus & XUL_SR_RX_FIFO_VALID_DATA ) != 0 )
{
/* A character is available - place it in the queue of received
characters. This might wake a task that was blocked waiting for
data. */
cChar = ( char ) XIo_In32( XPAR_RS232_UART_1_BASEADDR + XUL_RX_FIFO_OFFSET );
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
lDidSomething = pdTRUE;
}
if( ( ulISRStatus & XUL_SR_TX_FIFO_EMPTY ) != 0 )
{
/* There is space in the FIFO - if there are any characters queue for
transmission they can be sent to the UART now. This might unblock a
task that was waiting for space to become available on the Tx queue. */
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
{
XIo_Out32( XPAR_RS232_UART_1_BASEADDR + XUL_TX_FIFO_OFFSET, cChar );
lDidSomething = pdTRUE;
}
}
} while( lDidSomething == pdTRUE );
/* If we woke any tasks we may require a context switch. */
if( xHigherPriorityTaskWoken )
{
portYIELD_FROM_ISR();
}
}
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