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/*
FreeRTOS V8.0.1 - Copyright (C) 2014 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that has become a de facto standard. *
* *
* Help yourself get started quickly and support the FreeRTOS *
* project by purchasing a FreeRTOS tutorial book, reference *
* manual, or both from: http://www.FreeRTOS.org/Documentation *
* *
* Thank you! *
* *
***************************************************************************
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 from the following
link: http://www.freertos.org/a00114.html
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, books, training, latest versions,
license and Real Time Engineers Ltd. contact details.
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.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and 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 FOR USART1.
***Note*** This example uses queues to send each character into an interrupt
service routine and out of an interrupt service routine individually. This
is done to demonstrate queues being used in an interrupt, and to deliberately
load the system to test the FreeRTOS port. It is *NOT* meant to be an
example of an efficient implementation. An efficient implementation should
use FIFO's or DMA if available, and only use FreeRTOS API functions when
enough has been received to warrant a task being unblocked to process the
data.
*/
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
#include "semphr.h"
#include "comtest2.h"
/* Library includes. */
#include "asf.h"
/* Demo application includes. */
#include "demo_serial.h"
/*-----------------------------------------------------------*/
/* Misc defines. */
#define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
#define serNO_BLOCK ( ( TickType_t ) 0 )
#define serPMC_USART_ID ( BOARD_ID_USART )
/* The USART supported by this file. */
#define serUSART_PORT ( USART0 )
#define serUSART_IRQ ( USART0_IRQn )
/* Every bit in the interrupt mask. */
#define serMASK_ALL_INTERRUPTS ( 0xffffffffUL )
/*-----------------------------------------------------------*/
/* The queue used to hold received characters. */
static QueueHandle_t xRxedChars;
static QueueHandle_t xCharsForTx;
/*-----------------------------------------------------------*/
/*
* See the serial.h header file.
*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
uint32_t ulChar;
xComPortHandle xReturn;
const sam_usart_opt_t xUSARTSettings =
{
ulWantedBaud,
US_MR_CHRL_8_BIT,
US_MR_PAR_NO,
US_MR_NBSTOP_1_BIT,
US_MR_CHMODE_NORMAL,
0 /* Only used in IrDA mode. */
};
/* Create the queues used to hold Rx/Tx characters. */
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
/* If the queues were created correctly then setup the serial port
hardware. */
if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
{
/* Enable the peripheral clock in the PMC. */
pmc_enable_periph_clk( serPMC_USART_ID );
/* Configure USART in serial mode. */
usart_init_rs232( serUSART_PORT, &xUSARTSettings, sysclk_get_cpu_hz() );
/* Disable all the interrupts. */
usart_disable_interrupt( serUSART_PORT, serMASK_ALL_INTERRUPTS );
/* Enable the receiver and transmitter. */
usart_enable_tx( serUSART_PORT );
usart_enable_rx( serUSART_PORT );
/* Clear any characters before enabling interrupt. */
usart_getchar( serUSART_PORT, &ulChar );
/* Enable Rx end interrupt. */
usart_enable_interrupt( serUSART_PORT, US_IER_RXRDY );
/* Configure and enable interrupt of USART. */
NVIC_SetPriority( serUSART_IRQ, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
NVIC_EnableIRQ( serUSART_IRQ );
}
else
{
xReturn = ( xComPortHandle ) 0;
}
/* This demo file only supports a single port but we have to return
something to comply with the standard demo header file. */
return xReturn;
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
{
/* The port handle is not required as this driver only supports one port. */
( 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;
}
}
/*-----------------------------------------------------------*/
void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
{
signed char *pxNext;
/* A couple of parameters that this port does not use. */
( void ) usStringLength;
( void ) pxPort;
/* NOTE: This implementation does not handle the queue being full as no
block time is used! */
/* The port handle is not required as this driver only supports USART1. */
( void ) pxPort;
/* Send each character in the string, one at a time. */
pxNext = ( signed char * ) pcString;
while( *pxNext )
{
xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
pxNext++;
}
}
/*-----------------------------------------------------------*/
signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
{
signed portBASE_TYPE xReturn;
/* This simple example only supports one port. */
( void ) pxPort;
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
{
xReturn = pdPASS;
usart_enable_interrupt( serUSART_PORT, US_IER_TXRDY );
}
else
{
xReturn = pdFAIL;
}
return xReturn;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not supported as not required by the demo application. */
( void ) xPort;
}
/*-----------------------------------------------------------*/
/*
* It should be noted that the com test tasks (which use make use of this file)
* are included to demonstrate queues being used to communicate between tasks
* and interrupts, and to demonstrate a context switch being performed from
* inside an interrupt service routine. The serial driver used here is *not*
* intended to represent an efficient implementation. Real applications should
* make use of the USARTS peripheral DMA channel (PDC).
*/
void USART0_Handler( void )
{
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
uint8_t ucChar;
uint32_t ulChar;
uint32_t ulUSARTStatus, ulUSARTMask;
ulUSARTStatus = usart_get_status( serUSART_PORT );
ulUSARTMask = usart_get_interrupt_mask( serUSART_PORT );
ulUSARTStatus &= ulUSARTMask;
if( ( ulUSARTStatus & US_CSR_TXRDY ) != 0UL )
{
/* The interrupt was caused by the TX register becoming empty. Are
there any more characters to transmit? */
if( xQueueReceiveFromISR( xCharsForTx, &ucChar, &xHigherPriorityTaskWoken ) == pdTRUE )
{
/* A character was retrieved from the queue so can be sent to the
USART now. */
usart_putchar( serUSART_PORT, ( uint32_t ) ucChar );
}
else
{
usart_disable_interrupt( serUSART_PORT, US_IER_TXRDY );
}
}
if( ( ulUSARTStatus & US_CSR_RXRDY ) != 0UL )
{
/* A character has been received on the USART, send it to the Rx
handler task. */
usart_getchar( serUSART_PORT, &ulChar );
ucChar = ( uint8_t ) ( ulChar & 0xffUL );
xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
}
/* If sending or receiving from a queue has caused a task to unblock, and
the unblocked task has a priority equal to or higher than the currently
running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
will have automatically been set to pdTRUE within the queue send or receive
function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
directly to the higher priority unblocked task. */
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
}
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