You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
253 lines
9.1 KiB
C
253 lines
9.1 KiB
C
/*
|
|
FreeRTOS V6.1.0 - Copyright (C) 2010 Real Time Engineers Ltd.
|
|
|
|
***************************************************************************
|
|
* *
|
|
* If you are: *
|
|
* *
|
|
* + New to FreeRTOS, *
|
|
* + Wanting to learn FreeRTOS or multitasking in general quickly *
|
|
* + Looking for basic training, *
|
|
* + Wanting to improve your FreeRTOS skills and productivity *
|
|
* *
|
|
* then take a look at the FreeRTOS books - available as PDF or paperback *
|
|
* *
|
|
* "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
|
|
* http://www.FreeRTOS.org/Documentation *
|
|
* *
|
|
* A pdf reference manual is also available. Both are usually delivered *
|
|
* to your inbox within 20 minutes to two hours when purchased between 8am *
|
|
* and 8pm GMT (although please allow up to 24 hours in case of *
|
|
* exceptional circumstances). Thank you for your support! *
|
|
* *
|
|
***************************************************************************
|
|
|
|
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 exception 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. See the GNU General Public License for
|
|
more details. You should have received a copy of the GNU General Public
|
|
License and the FreeRTOS license exception along with FreeRTOS; if not it
|
|
can be viewed here: http://www.freertos.org/a00114.html and also obtained
|
|
by writing to Richard Barry, contact details for whom are available on the
|
|
FreeRTOS WEB site.
|
|
|
|
1 tab == 4 spaces!
|
|
|
|
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 short ) 1 )
|
|
#define serRX_ENABLE ( ( unsigned short ) 1 )
|
|
#define serHIGH_SPEED ( ( unsigned short ) 1 )
|
|
#define serCONTINUOUS_RX ( ( unsigned short ) 1 )
|
|
#define serCLEAR_OVERRUN ( ( unsigned short ) 0 )
|
|
#define serINTERRUPT_ENABLED ( ( unsigned short ) 1 )
|
|
#define serINTERRUPT_DISABLED ( ( unsigned short ) 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 long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
|
|
{
|
|
unsigned long ulBaud;
|
|
|
|
/* Calculate the baud rate generator constant.
|
|
SPBRG = ( (FOSC / Desired Baud Rate) / 16 ) - 1 */
|
|
ulBaud = configCPU_CLOCK_HZ / ulWantedBaud;
|
|
ulBaud /= ( unsigned long ) 16;
|
|
ulBaud -= ( unsigned long ) 1;
|
|
|
|
/* Create the queues used by the ISR's to interface to tasks. */
|
|
xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
|
|
xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
|
|
|
|
portENTER_CRITICAL();
|
|
{
|
|
/* Start with config registers cleared, so we can just set the wanted
|
|
bits. */
|
|
TXSTA = ( unsigned short ) 0;
|
|
RCSTA = ( unsigned short ) 0;
|
|
|
|
/* Set the baud rate generator using the above calculated constant. */
|
|
SPBRG = ( unsigned char ) 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 char *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 char 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 )
|
|
{
|
|
char 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 )
|
|
{
|
|
char 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;
|
|
}
|
|
}
|
|
|
|
|
|
|