/* FreeRTOS.org V5.1.1 - 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. * * See http://www.OpenRTOS.com for details of the services we provide to * * expedite your project. * * * *************************************************************************** *************************************************************************** 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; } }