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/*
FreeRTOS V8.2.2 - Copyright (C) 2015 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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. Full license text is available on the following
link: http://www.freertos.org/a00114.html
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that is more than just the market leader, it *
* is the industry's de facto standard. *
* *
* Help yourself get started quickly while simultaneously helping *
* to support the FreeRTOS project by purchasing a FreeRTOS *
* tutorial book, reference manual, or both: *
* http://www.FreeRTOS.org/Documentation *
* *
***************************************************************************
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
the FAQ page "My application does not run, what could be wrong?". Have you
defined configASSERT()?
http://www.FreeRTOS.org/support - In return for receiving this top quality
embedded software for free we request you assist our global community by
participating in the support forum.
http://www.FreeRTOS.org/training - Investing in training allows your team to
be as productive as possible as early as possible. Now you can receive
FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
Ltd, and the world's leading authority on the world's leading RTOS.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and commercial middleware.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
1 tab == 4 spaces!
*/
/*
* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
*
* This file only supports UART 2
*/
/* Standard includes. */
#include <stdlib.h>
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "task.h"
/* Demo application includes. */
#include "serial.h"
/* The queue used to hold received characters. */
static QueueHandle_t xRxedChars;
/* The queue used to hold characters waiting transmission. */
static QueueHandle_t xCharsForTx;
static volatile short sTHREEmpty;
/*-----------------------------------------------------------*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
portENTER_CRITICAL();
{
/* Create the queues used by the com test task. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
/* Initialize UART asynchronous mode */
BGR02 = configPER_CLOCK_HZ / ulWantedBaud;
SCR02 = 0x17; /* 8N1 */
SMR02 = 0x0d; /* enable SOT3, Reset, normal mode */
SSR02 = 0x02; /* LSB first, enable receive interrupts */
PFR20_D0 = 1; /* enable UART */
PFR20_D1 = 1; /* enable UART */
EPFR20_D1 = 0; /* enable UART */
}
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 char *pcRxedChar, TickType_t xBlockTime )
{
/* 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, TickType_t xBlockTime )
{
signed portBASE_TYPE xReturn;
/* Transmit a character. */
portENTER_CRITICAL();
{
if( sTHREEmpty == pdTRUE )
{
/* If sTHREEmpty is true then the UART Tx ISR has indicated that
there are no characters queued to be transmitted - so we can
write the character directly to the shift Tx register. */
sTHREEmpty = pdFALSE;
TDR02 = cOutChar;
xReturn = pdPASS;
}
else
{
/* sTHREEmpty is false, so there are still characters waiting to be
transmitted. We have to queue this character so it gets
transmitted in turn. */
/* Return false if after the block time there is no room on the Tx
queue. It is ok to block inside a critical section as each task
maintains it's own critical section status. */
if (xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdTRUE)
{
xReturn = pdPASS;
}
else
{
xReturn = pdFAIL;
}
}
if (pdPASS == xReturn)
{
/* Turn on the Tx interrupt so the ISR will remove the character from the
queue and send it. This does not need to be in a critical section as
if the interrupt has already removed the character the next interrupt
will simply turn off the Tx interrupt again. */
SSR02_TIE = 1;
}
}
portEXIT_CRITICAL();
return pdPASS;
}
/*-----------------------------------------------------------*/
/*
* UART RX interrupt service routine.
*/
__interrupt void UART2_RxISR (void)
{
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* Get the character from the UART and post it on the queue of Rxed
characters. */
cChar = RDR02;
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
if( xHigherPriorityTaskWoken )
{
/*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. */
portYIELD_FROM_ISR();
}
}
/*-----------------------------------------------------------*/
/*
* UART Tx interrupt service routine.
*/
__interrupt void UART2_TxISR (void)
{
signed char cChar;
signed portBASE_TYPE xTaskWoken = pdFALSE;
/* The previous character has been transmitted. See if there are any
further characters waiting transmission. */
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
{
/* There was another character queued - transmit it now. */
TDR02 = cChar;
}
else
{
/* There were no other characters to transmit. */
sTHREEmpty = pdTRUE;
/* Disable transmit interrupts */
SSR02_TIE = 0;
}
}
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