/* | |
FreeRTOS.org V5.1.0 - Copyright (C) 2003-2008 Richard Barry. | |
This file is part of the FreeRTOS.org distribution. | |
FreeRTOS.org is free software; you can redistribute it and/or modify | |
it under the terms of the GNU General Public License as published by | |
the Free Software Foundation; either version 2 of the License, or | |
(at your option) any later version. | |
FreeRTOS.org 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.org; if not, write to the Free Software | |
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
A special exception to the GPL can be applied should you wish to distribute | |
a combined work that includes FreeRTOS.org, without being obliged to provide | |
the source code for any proprietary components. See the licensing section | |
of http://www.FreeRTOS.org for full details of how and when the exception | |
can be applied. | |
*************************************************************************** | |
*************************************************************************** | |
* * | |
* SAVE TIME AND MONEY! We can port FreeRTOS.org to your own hardware, * | |
* and even write all or part of your application on your behalf. * | |
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*************************************************************************** | |
*************************************************************************** | |
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. | |
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*/ | |
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER for port 1. | |
Note that this driver is written to test the RTOS port and is not intended | |
to represent an optimised solution. In particular no use is made of the DMA | |
peripheral. */ | |
/* Standard include files. */ | |
#include <stdlib.h> | |
/* Scheduler include files. */ | |
#include "FreeRTOS.h" | |
#include "queue.h" | |
#include "task.h" | |
/* Demo application include files. */ | |
#include "serial.h" | |
/* The queues used to communicate between the task code and the interrupt | |
service routines. */ | |
static xQueueHandle xRxedChars; | |
static xQueueHandle xCharsForTx; | |
/* Hardware specific constants. */ | |
#define serTX_INTERRUPT ( ( unsigned portCHAR ) 0x80 ) | |
#define serRX_INTERRUPT ( ( unsigned portCHAR ) 0x40 ) | |
#define serTX_ENABLE ( ( unsigned portCHAR ) 0x20 ) | |
#define serRX_ENABLE ( ( unsigned portCHAR ) 0x10 ) | |
/* Macros to turn on and off the serial port THRE interrupt while leaving the | |
other register bits in their correct state. The Rx interrupt is always | |
enabled. */ | |
#define serTX_INTERRUPT_ON() SCR1 = serTX_INTERRUPT | serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE; | |
#define serTX_INTERRUPT_OFF() SCR1 = serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE; | |
/* Bit used to switch on the channel 1 serial port in the module stop | |
register. */ | |
#define serMSTP6 ( ( unsigned portSHORT ) 0x0040 ) | |
/* Interrupt service routines. Note that the Rx and Tx service routines can | |
cause a context switch and are therefore defined with the saveall attribute in | |
addition to the interrupt_handler attribute. See the FreeRTOS.org WEB site | |
documentation for a full explanation.*/ | |
void vCOM_1_Rx_ISR( void ) __attribute__ ( ( saveall, interrupt_handler ) ); | |
void vCOM_1_Tx_ISR( void ) __attribute__ ( ( saveall, interrupt_handler ) ); | |
void vCOM_1_Error_ISR( void ) __attribute__ ( ( interrupt_handler ) ); | |
/*-----------------------------------------------------------*/ | |
/* | |
* Initialise port 1 for interrupt driven communications. | |
*/ | |
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
{ | |
/* Create the queues used to communicate between the tasks and the | |
interrupt service routines. */ | |
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) ); | |
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) ); | |
/* No parity, 8 data bits and 1 stop bit is the default so does not require | |
configuration - setup the remains of the hardware. */ | |
portENTER_CRITICAL(); | |
{ | |
/* Turn channel 1 on. */ | |
MSTPCR &= ~serMSTP6; | |
/* Enable the channels and the Rx interrupt. The Tx interrupt is only | |
enabled when data is being transmitted. */ | |
SCR1 = serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE; | |
/* Bit rate settings for 22.1184MHz clock only!. */ | |
switch( ulWantedBaud ) | |
{ | |
case 4800 : BRR1 = 143; | |
break; | |
case 9600 : BRR1 = 71; | |
break; | |
case 19200 : BRR1 = 35; | |
break; | |
case 38400 : BRR1 = 17; | |
break; | |
case 57600 : BRR1 = 11; | |
break; | |
case 115200 : BRR1 = 5; | |
break; | |
default : BRR1 = 5; | |
break; | |
} | |
} | |
portEXIT_CRITICAL(); | |
/* Unlike some ports, this driver 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 ) | |
{ | |
/* Get the next character from the buffer queue. 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 ) | |
{ | |
signed portBASE_TYPE xReturn = pdPASS; | |
/* Return false if after the block time there is no room on the Tx queue. */ | |
portENTER_CRITICAL(); | |
{ | |
/* Send a character to the queue of characters waiting transmission. | |
The queue is serviced by the Tx ISR. */ | |
if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS ) | |
{ | |
/* Could not post onto the queue. */ | |
xReturn = pdFAIL; | |
} | |
else | |
{ | |
/* The message was posted onto the queue so we turn on the Tx | |
interrupt to allow the Tx ISR to remove the character from the | |
queue. */ | |
serTX_INTERRUPT_ON(); | |
} | |
} | |
portEXIT_CRITICAL(); | |
return xReturn; | |
} | |
/*-----------------------------------------------------------*/ | |
void vSerialClose( xComPortHandle xPort ) | |
{ | |
/* Not supported. */ | |
( void ) xPort; | |
} | |
/*-----------------------------------------------------------*/ | |
void vCOM_1_Rx_ISR( void ) | |
{ | |
/* This can cause a context switch so this macro must be the first line | |
in the function. */ | |
portENTER_SWITCHING_ISR(); | |
/* As this is a switching ISR the local variables must be declared as | |
static. */ | |
static portCHAR cRxByte; | |
static portBASE_TYPE xHigherPriorityTaskWoken; | |
xHigherPriorityTaskWoken = pdFALSE; | |
/* Get the character. */ | |
cRxByte = RDR1; | |
/* Post the character onto the queue of received characters - noting | |
whether or not this wakes a task. */ | |
xQueueSendFromISR( xRxedChars, &cRxByte, &xHigherPriorityTaskWoken ); | |
/* Clear the interrupt. */ | |
SSR1 &= ~serRX_INTERRUPT; | |
/* This must be the last line in the function. We pass cTaskWokenByPost so | |
a context switch will occur if the received character woke a task that has | |
a priority higher than the task we interrupted. */ | |
portEXIT_SWITCHING_ISR( xHigherPriorityTaskWoken ); | |
} | |
/*-----------------------------------------------------------*/ | |
void vCOM_1_Tx_ISR( void ) | |
{ | |
/* This can cause a context switch so this macro must be the first line | |
in the function. */ | |
portENTER_SWITCHING_ISR(); | |
/* As this is a switching ISR the local variables must be declared as | |
static. */ | |
static portCHAR cTxByte; | |
static signed portBASE_TYPE xTaskWokenByTx; | |
/* This variable is static so must be explicitly reinitialised each | |
time the function executes. */ | |
xTaskWokenByTx = pdFALSE; | |
/* The interrupt was caused by the THR becoming empty. Are there any | |
more characters to transmit? Note whether or not the Tx interrupt has | |
woken a task. */ | |
if( xQueueReceiveFromISR( xCharsForTx, &cTxByte, &xTaskWokenByTx ) == pdTRUE ) | |
{ | |
/* A character was retrieved from the queue so can be sent to the | |
THR now. */ | |
TDR1 = cTxByte; | |
/* Clear the interrupt. */ | |
SSR1 &= ~serTX_INTERRUPT; | |
} | |
else | |
{ | |
/* Queue empty, nothing to send so turn off the Tx interrupt. */ | |
serTX_INTERRUPT_OFF(); | |
} | |
/* This must be the last line in the function. We pass cTaskWokenByTx so | |
a context switch will occur if the Tx'ed character woke a task that has | |
a priority higher than the task we interrupted. */ | |
portEXIT_SWITCHING_ISR( xTaskWokenByTx ); | |
} | |
/*-----------------------------------------------------------*/ | |
/* | |
* This ISR cannot cause a context switch so requires no special | |
* considerations. | |
*/ | |
void vCOM_1_Error_ISR( void ) | |
{ | |
volatile unsigned portCHAR ucIn; | |
ucIn = SSR1; | |
SSR1 = 0; | |
} | |