/* | |
FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 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. | |
*************************************************************************** | |
*************************************************************************** | |
* * | |
* Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation * | |
* * | |
* This is a concise, step by step, 'hands on' guide that describes both * | |
* general multitasking concepts and FreeRTOS specifics. It presents and * | |
* explains numerous examples that are written using the FreeRTOS API. * | |
* Full source code for all the examples is provided in an accompanying * | |
* .zip file. * | |
* * | |
*************************************************************************** | |
*************************************************************************** | |
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 V1.2.5 | |
+ Clear overrun errors in the Rx ISR. Overrun errors prevent any further | |
characters being received. | |
Changes from V2.0.0 | |
+ Use portTickType in place of unsigned pdLONG for delay periods. | |
+ cQueueReieveFromISR() used in place of xQueueReceive() in ISR. | |
*/ | |
/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */ | |
/* Scheduler header files. */ | |
#include "FreeRTOS.h" | |
#include "task.h" | |
#include "serial.h" | |
#include "queue.h" | |
/* | |
* Prototypes for ISR's. The PIC architecture means that these functions | |
* have to be called from port.c. The prototypes are not however included | |
* in the header as the header is common to all ports. | |
*/ | |
void vSerialTxISR( void ); | |
void vSerialRxISR( void ); | |
/* Hardware pin definitions. */ | |
#define serTX_PIN TRISCbits.TRISC6 | |
#define serRX_PIN TRISCbits.TRISC7 | |
/* Bit/register definitions. */ | |
#define serINPUT ( 1 ) | |
#define serOUTPUT ( 0 ) | |
#define serTX_ENABLE ( ( unsigned portSHORT ) 1 ) | |
#define serRX_ENABLE ( ( unsigned portSHORT ) 1 ) | |
#define serHIGH_SPEED ( ( unsigned portSHORT ) 1 ) | |
#define serCONTINUOUS_RX ( ( unsigned portSHORT ) 1 ) | |
#define serCLEAR_OVERRUN ( ( unsigned portSHORT ) 0 ) | |
#define serINTERRUPT_ENABLED ( ( unsigned portSHORT ) 1 ) | |
#define serINTERRUPT_DISABLED ( ( unsigned portSHORT ) 0 ) | |
/* All ISR's use the PIC18 low priority interrupt. */ | |
#define serLOW_PRIORITY ( 0 ) | |
/*-----------------------------------------------------------*/ | |
/* Queues to interface between comms API and interrupt routines. */ | |
static xQueueHandle xRxedChars; | |
static xQueueHandle xCharsForTx; | |
/*-----------------------------------------------------------*/ | |
xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) | |
{ | |
unsigned portLONG ulBaud; | |
/* Calculate the baud rate generator constant. | |
SPBRG = ( (FOSC / Desired Baud Rate) / 16 ) - 1 */ | |
ulBaud = configCPU_CLOCK_HZ / ulWantedBaud; | |
ulBaud /= ( unsigned portLONG ) 16; | |
ulBaud -= ( unsigned portLONG ) 1; | |
/* Create the queues used by the ISR's to interface to tasks. */ | |
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( portCHAR ) ); | |
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( portCHAR ) ); | |
portENTER_CRITICAL(); | |
{ | |
/* Start with config registers cleared, so we can just set the wanted | |
bits. */ | |
TXSTA = ( unsigned portSHORT ) 0; | |
RCSTA = ( unsigned portSHORT ) 0; | |
/* Set the baud rate generator using the above calculated constant. */ | |
SPBRG = ( unsigned portCHAR ) ulBaud; | |
/* Setup the IO pins to enable the USART IO. */ | |
serTX_PIN = serOUTPUT; | |
serRX_PIN = serINPUT; | |
/* Set the serial interrupts to use the same priority as the tick. */ | |
IPR1bits.TXIP = serLOW_PRIORITY; | |
IPR1bits.RCIP = serLOW_PRIORITY; | |
/* Setup Tx configuration. */ | |
TXSTAbits.BRGH = serHIGH_SPEED; | |
TXSTAbits.TXEN = serTX_ENABLE; | |
/* Setup Rx configuration. */ | |
RCSTAbits.SPEN = serRX_ENABLE; | |
RCSTAbits.CREN = serCONTINUOUS_RX; | |
/* Enable the Rx interrupt now, the Tx interrupt will get enabled when | |
we have data to send. */ | |
PIE1bits.RCIE = serINTERRUPT_ENABLED; | |
} | |
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; | |
} | |
/*-----------------------------------------------------------*/ | |
xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned portBASE_TYPE uxBufferLength ) | |
{ | |
/* This is not implemented in this port. | |
Use xSerialPortInitMinimal() instead. */ | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType 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; | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime ) | |
{ | |
/* Return false if after the block time there is no room on the Tx queue. */ | |
if( xQueueSend( xCharsForTx, ( const void * ) &cOutChar, xBlockTime ) != pdPASS ) | |
{ | |
return pdFAIL; | |
} | |
/* Turn interrupt on - ensure the compiler only generates a single | |
instruction for this. */ | |
PIE1bits.TXIE = serINTERRUPT_ENABLED; | |
return pdPASS; | |
} | |
/*-----------------------------------------------------------*/ | |
void vSerialClose( xComPortHandle xPort ) | |
{ | |
/* Not implemented for this port. | |
To implement, turn off the interrupts and delete the memory | |
allocated to the queues. */ | |
} | |
/*-----------------------------------------------------------*/ | |
#pragma interruptlow vSerialRxISR save=PRODH, PRODL, TABLAT, section(".tmpdata") | |
void vSerialRxISR( void ) | |
{ | |
portCHAR cChar; | |
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 = RCREG; | |
/* Clear any overrun errors. */ | |
if( RCSTAbits.OERR ) | |
{ | |
RCSTAbits.CREN = serCLEAR_OVERRUN; | |
RCSTAbits.CREN = serCONTINUOUS_RX; | |
} | |
xQueueSendFromISR( xRxedChars, ( const void * ) &cChar, &xHigherPriorityTaskWoken ); | |
if( xHigherPriorityTaskWoken ) | |
{ | |
taskYIELD(); | |
} | |
} | |
/*-----------------------------------------------------------*/ | |
#pragma interruptlow vSerialTxISR save=PRODH, PRODL, TABLAT, section(".tmpdata") | |
void vSerialTxISR( void ) | |
{ | |
portCHAR cChar, cTaskWoken = pdFALSE; | |
if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE ) | |
{ | |
/* Send the next character queued for Tx. */ | |
TXREG = cChar; | |
} | |
else | |
{ | |
/* Queue empty, nothing to send. */ | |
PIE1bits.TXIE = serINTERRUPT_DISABLED; | |
} | |
} | |