/* FreeRTOS V4.0.1 - Copyright (C) 2003-2006 Richard Barry. 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 as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. 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 along with FreeRTOS; 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, 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. *************************************************************************** See http://www.FreeRTOS.org for documentation, latest information, license and contact details. Please ensure to read the configuration and relevant port sections of the online documentation. *************************************************************************** */ /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. * * This file only supports UART 1 */ /* Standard includes. */ #include /* Scheduler includes. */ #include "FreeRTOS.h" #include "queue.h" #include "task.h" /* Demo application includes. */ #include "serial.h" /* Constants required to setup the hardware. */ #define serTX_AND_RX ( ( unsigned portCHAR ) 0x03 ) /* Misc. constants. */ #define serNO_BLOCK ( ( portTickType ) 0 ) /* Enable the UART Tx interrupt. */ #define vInterruptOn() IFG2 |= UTXIFG1 /* The queue used to hold received characters. */ static xQueueHandle xRxedChars; /* The queue used to hold characters waiting transmission. */ static xQueueHandle xCharsForTx; static volatile portSHORT sTHREEmpty; /*-----------------------------------------------------------*/ xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) { unsigned portLONG ulBaudRateCount; /* Initialise the hardware. */ /* Generate the baud rate constants for the wanted baud rate. */ ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud; portENTER_CRITICAL(); { /* Create the queues used by the com test task. */ xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) ); xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) ); /* Reset UART. */ UCTL1 |= SWRST; /* Set pin function. */ P4SEL |= serTX_AND_RX; /* All other bits remain at zero for n, 8, 1 interrupt driven operation. LOOPBACK MODE!*/ U1CTL |= CHAR + LISTEN; U1TCTL |= SSEL1; /* Setup baud rate low byte. */ U1BR0 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff ); /* Setup baud rate high byte. */ ulBaudRateCount >>= 8UL; U1BR1 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff ); /* Enable ports. */ ME2 |= UTXE1 + URXE1; /* Set. */ UCTL1 &= ~SWRST; /* Nothing in the buffer yet. */ sTHREEmpty = pdTRUE; /* Enable interrupts. */ IE2 |= URXIE1 + UTXIE1; } 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; } /*-----------------------------------------------------------*/ signed 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; } } /*-----------------------------------------------------------*/ signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime ) { signed portBASE_TYPE xReturn; /* Transmit a character. */ portENTER_CRITICAL(); { if( sTHREEmpty == pdTRUE ) { /* If sTHREEmpty is true then the UART Tx ISR has indicated that there are no characters queued to be transmitted - so we can write the character directly to the shift Tx register. */ sTHREEmpty = pdFALSE; U1TXBUF = cOutChar; xReturn = pdPASS; } else { /* sTHREEmpty is false, so there are still characters waiting to be transmitted. We have to queue this character so it gets transmitted in turn. */ /* Return false if after the block time there is no room on the Tx queue. It is ok to block inside a critical section as each task maintains it's own critical section status. */ xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime ); /* Depending on queue sizing and task prioritisation: While we were blocked waiting to post on the queue interrupts were not disabled. It is possible that the serial ISR has emptied the Tx queue, in which case we need to start the Tx off again writing directly to the Tx register. */ if( ( sTHREEmpty == pdTRUE ) && ( xReturn == pdPASS ) ) { /* Get back the character we just posted. */ xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK ); sTHREEmpty = pdFALSE; U1TXBUF = cOutChar; } } } portEXIT_CRITICAL(); return pdPASS; } /*-----------------------------------------------------------*/ #ifdef MSP_ROWLEY_RB_PORT /* Serial interrupt service routines for the RB port. */ /* * UART RX interrupt service routine. */ void vRxISR( void ) __interrupt[ UART1RX_VECTOR ] { signed portCHAR cChar; /* Get the character from the UART and post it on the queue of Rxed characters. */ cChar = U1RXBUF; if( xQueueSendFromISR( xRxedChars, &cChar, pdFALSE ) ) { /*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. */ taskYIELD(); } } /*-----------------------------------------------------------*/ /* * UART Tx interrupt service routine. */ void vTxISR( void ) __interrupt[ UART1TX_VECTOR ] { signed portCHAR cChar; portBASE_TYPE xTaskWoken; /* The previous character has been transmitted. See if there are any further characters waiting transmission. */ if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE ) { /* There was another character queued - transmit it now. */ U1TXBUF = cChar; } else { /* There were no other characters to transmit. */ sTHREEmpty = pdTRUE; } } #endif /*-----------------------------------------------------------*/ #ifdef MSP_ROWLEY_MP_PORT /* Serial port interrupts for the alternative port code. */ void ISRCom1Rx( void ) { signed portCHAR cChar; /* Get the character from the UART and post it on the queue of Rxed characters. */ cChar = U1RXBUF; if( xQueueSendFromISR( xRxedChars, &cChar, pdFALSE ) ) { /*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. */ portEXIT_SWITCHING_ISR( pdTRUE ); } } /*-----------------------------------------------------------*/ void ISRCom1Tx( void ) { signed portCHAR cChar; portBASE_TYPE xTaskWoken; /* The previous character has been transmitted. See if there are any further characters waiting transmission. */ if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE ) { /* There was another character queued - transmit it now. */ U1TXBUF = cChar; } else { /* There were no other characters to transmit. */ sTHREEmpty = pdTRUE; } } #endif /*-----------------------------------------------------------*/