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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [MB91460_Softune/] [SRC/] [serial/] [serial.c] - Rev 584
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/* FreeRTOS V6.1.1 - Copyright (C) 2011 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. */ /* * BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. * * This file only supports UART 2 */ /* Standard includes. */ #include <stdlib.h> /* Scheduler includes. */ #include "FreeRTOS.h" #include "queue.h" #include "task.h" /* Demo application includes. */ #include "serial.h" /* 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 ) { 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 ) ); /* Initialize UART asynchronous mode */ BGR02 = configPER_CLOCK_HZ / ulWantedBaud; SCR02 = 0x17; /* 8N1 */ SMR02 = 0x0d; /* enable SOT3, Reset, normal mode */ SSR02 = 0x02; /* LSB first, enable receive interrupts */ PFR20_D0 = 1; /* enable UART */ PFR20_D1 = 1; /* enable UART */ EPFR20_D1 = 0; /* enable UART */ } 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; TDR02 = 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. */ if (xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdTRUE) { xReturn = pdPASS; } else { xReturn = pdFAIL; } } if (pdPASS == xReturn) { /* Turn on the Tx interrupt so the ISR will remove the character from the queue and send it. This does not need to be in a critical section as if the interrupt has already removed the character the next interrupt will simply turn off the Tx interrupt again. */ SSR02_TIE = 1; } } portEXIT_CRITICAL(); return pdPASS; } /*-----------------------------------------------------------*/ /* * UART RX interrupt service routine. */ __interrupt void UART2_RxISR (void) { signed portCHAR cChar; portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; /* Get the character from the UART and post it on the queue of Rxed characters. */ cChar = RDR02; xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken ); if( xHigherPriorityTaskWoken ) { /*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. */ portYIELD_FROM_ISR(); } } /*-----------------------------------------------------------*/ /* * UART Tx interrupt service routine. */ __interrupt void UART2_TxISR (void) { signed portCHAR cChar; signed portBASE_TYPE xTaskWoken = pdFALSE; /* 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. */ TDR02 = cChar; } else { /* There were no other characters to transmit. */ sTHREEmpty = pdTRUE; /* Disable transmit interrupts */ SSR02_TIE = 0; } }