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Before changing headers to V6 and changing portLONG, portSHORt and portCHAR to their standard C types.

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Richard Barry 2009-10-05 08:33:08 +00:00
parent 3dfbb349ca
commit 5c64e1fad9
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20091005/Demo/AVR_ATMega323_WinAVR/serial/serial.c Normal file
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/*
FreeRTOS V5.4.2 - Copyright (C) 2009 Real Time Engineers Ltd.
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.
Alternative commercial license and support terms are also available upon
request. See the licensing section of http://www.FreeRTOS.org for full
license details.
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 along
with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
Temple Place, Suite 330, Boston, MA 02111-1307 USA.
***************************************************************************
* *
* Looking for a quick start? Then check out the FreeRTOS eBook! *
* See http://www.FreeRTOS.org/Documentation for details *
* *
***************************************************************************
1 tab == 4 spaces!
Please ensure to read the configuration and relevant port sections of the
online documentation.
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.
*/
/*
Changes from V1.2.3
+ The function xPortInitMinimal() has been renamed to
xSerialPortInitMinimal() and the function xPortInit() has been renamed
to xSerialPortInit().
Changes from V2.0.0
+ Delay periods are now specified using variables and constants of
portTickType rather than unsigned portLONG.
+ xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR.
Changes from V2.6.0
+ Replaced the inb() and outb() functions with direct memory
access. This allows the port to be built with the 20050414 build of
WinAVR.
*/
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
#include <stdlib.h>
#include <avr/interrupt.h>
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
#include "serial.h"
#define serBAUD_DIV_CONSTANT ( ( unsigned portLONG ) 16 )
/* Constants for writing to UCSRB. */
#define serRX_INT_ENABLE ( ( unsigned portCHAR ) 0x80 )
#define serRX_ENABLE ( ( unsigned portCHAR ) 0x10 )
#define serTX_ENABLE ( ( unsigned portCHAR ) 0x08 )
#define serTX_INT_ENABLE ( ( unsigned portCHAR ) 0x20 )
/* Constants for writing to UCSRC. */
#define serUCSRC_SELECT ( ( unsigned portCHAR ) 0x80 )
#define serEIGHT_DATA_BITS ( ( unsigned portCHAR ) 0x06 )
static xQueueHandle xRxedChars;
static xQueueHandle xCharsForTx;
#define vInterruptOn() \
{ \
unsigned portCHAR ucByte; \
\
ucByte = UCSRB; \
ucByte |= serTX_INT_ENABLE; \
UCSRB = ucByte; \
}
/*-----------------------------------------------------------*/
#define vInterruptOff() \
{ \
unsigned portCHAR ucInByte; \
\
ucInByte = UCSRB; \
ucInByte &= ~serTX_INT_ENABLE; \
UCSRB = ucInByte; \
}
/*-----------------------------------------------------------*/
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
unsigned portLONG ulBaudRateCounter;
unsigned portCHAR ucByte;
portENTER_CRITICAL();
{
/* 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 ) );
/* Calculate the baud rate register value from the equation in the
data sheet. */
ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned portLONG ) 1;
/* Set the baud rate. */
ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
UBRRL = ucByte;
ulBaudRateCounter >>= ( unsigned portLONG ) 8;
ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
UBRRH = ucByte;
/* Enable the Rx interrupt. The Tx interrupt will get enabled
later. Also enable the Rx and Tx. */
UCSRB = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
/* Set the data bits to 8. */
UCSRC = ( serUCSRC_SELECT | serEIGHT_DATA_BITS );
}
portEXIT_CRITICAL();
/* Unlike other ports, this serial code does not allow for more than one
com port. We therefore don't return a pointer to a port structure and can
instead just return NULL. */
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;
}
vInterruptOn();
return pdPASS;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
unsigned portCHAR ucByte;
/* The parameter is not used. */
( void ) xPort;
/* Turn off the interrupts. We may also want to delete the queues and/or
re-install the original ISR. */
portENTER_CRITICAL();
{
vInterruptOff();
ucByte = UCSRB;
ucByte &= ~serRX_INT_ENABLE;
UCSRB = ucByte;
}
portEXIT_CRITICAL();
}
/*-----------------------------------------------------------*/
SIGNAL( SIG_UART_RECV )
{
signed portCHAR cChar;
signed portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* Get the character and post it on the queue of Rxed characters.
If the post causes a task to wake force a context switch as the woken task
may have a higher priority than the task we have interrupted. */
cChar = UDR;
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
if( xHigherPriorityTaskWoken != pdFALSE )
{
taskYIELD();
}
}
/*-----------------------------------------------------------*/
SIGNAL( SIG_UART_DATA )
{
signed portCHAR cChar, cTaskWoken;
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
{
/* Send the next character queued for Tx. */
UDR = cChar;
}
else
{
/* Queue empty, nothing to send. */
vInterruptOff();
}
}