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/*
FreeRTOS V7.5.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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 UART0.
*/
/* Library includes. */
#include "uart.h"
#include "gpio.h"
#include "eic.h"
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "queue.h"
/* Demo application includes. */
#include "serial.h"
#define UART0_Rx_Pin ( 0x0001<< 8 )
#define UART0_Tx_Pin ( 0x0001<< 9 )
#define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
#define serNO_BLOCK ( ( portTickType ) 0 )
/* Macros to turn on and off the Tx empty interrupt. */
#define serINTERRUPT_ON() UART0->IER |= UART_TxHalfEmpty
#define serINTERRUPT_OFF() UART0->IER &= ~UART_TxHalfEmpty
/*-----------------------------------------------------------*/
/* Queues used to hold received characters, and characters waiting to be
transmitted. */
static xQueueHandle xRxedChars;
static xQueueHandle xCharsForTx;
/*-----------------------------------------------------------*/
/* Interrupt entry point written in the assembler file serialISR.s79. */
extern void vSerialISREntry( void );
/* The interrupt service routine - called from the assembly entry point. */
__arm void vSerialISR( void );
/*-----------------------------------------------------------*/
/*
* See the serial2.h header file.
*/
xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
{
xComPortHandle xReturn;
/* 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 ) );
/* If the queues were created correctly then setup the serial port
hardware. */
if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
{
portENTER_CRITICAL();
{
/* Setup the UART port pins. */
GPIO_Config( GPIO0, UART0_Tx_Pin, GPIO_AF_PP );
GPIO_Config( GPIO0, UART0_Rx_Pin, GPIO_IN_TRI_CMOS );
/* Configure the UART. */
UART_OnOffConfig( UART0, ENABLE );
UART_FifoConfig( UART0, DISABLE );
UART_FifoReset( UART0, UART_RxFIFO );
UART_FifoReset( UART0, UART_TxFIFO );
UART_LoopBackConfig(UART0, DISABLE );
UART_Config( UART0, ulWantedBaud, UART_NO_PARITY, UART_1_StopBits, UARTM_8D );
UART_RxConfig( UART0, ENABLE );
/* Configure the IEC for the UART interrupts. */
EIC_IRQChannelPriorityConfig( UART0_IRQChannel, 1 );
EIC_IRQChannelConfig( UART0_IRQChannel, ENABLE );
EIC_IRQConfig( ENABLE );
UART_ItConfig( UART0, UART_RxBufFull, ENABLE );
}
portEXIT_CRITICAL();
}
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, portTickType 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 UART0. */
( 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, portTickType xBlockTime )
{
/* Place the character in the queue of characters to be transmitted. */
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
{
return pdFAIL;
}
/* 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. */
serINTERRUPT_ON();
return pdPASS;
}
/*-----------------------------------------------------------*/
void vSerialClose( xComPortHandle xPort )
{
/* Not supported as not required by the demo application. */
}
/*-----------------------------------------------------------*/
/* Serial port ISR. This can cause a context switch so is not defined as a
standard ISR using the __irq keyword. Instead a wrapper function is defined
within serialISR.s79 which in turn calls this function. See the port
documentation on the FreeRTOS.org website for more information. */
__arm void vSerialISR( void )
{
unsigned short usStatus;
signed char cChar;
portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
/* What caused the interrupt? */
usStatus = UART_FlagStatus( UART0 );
if( usStatus & UART_TxHalfEmpty )
{
/* The interrupt was caused by the THR becoming empty. Are there any
more characters to transmit? */
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
{
/* A character was retrieved from the queue so can be sent to the
THR now. */
UART0->TxBUFR = cChar;
}
else
{
/* Queue empty, nothing to send so turn off the Tx interrupt. */
serINTERRUPT_OFF();
}
}
if( usStatus & UART_RxBufFull )
{
/* The interrupt was caused by a character being received. Grab the
character from the RHR and place it in the queue of received
characters. */
cChar = UART0->RxBUFR;
xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
}
/* If a task was woken by either a character being received or a character
being transmitted then we may need to switch to another task. */
portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
/* End the interrupt in the EIC. */
portCLEAR_EIC();
}
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