/* FreeRTOS V7.5.3 - Copyright (C) 2013 Real Time Engineers Ltd. All rights reserved VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. *************************************************************************** * * * FreeRTOS provides completely free yet professionally developed, * * robust, strictly quality controlled, supported, and cross * * platform software that has become a de facto standard. * * * * Help yourself get started quickly and support the FreeRTOS * * project by purchasing a FreeRTOS tutorial book, reference * * manual, or both from: http://www.FreeRTOS.org/Documentation * * * * Thank you! * * * *************************************************************************** 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 modification 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. Full license text is available from the following link: http://www.freertos.org/a00114.html 1 tab == 4 spaces! *************************************************************************** * * * Having a problem? Start by reading the FAQ "My application does * * not run, what could be wrong?" * * * * http://www.FreeRTOS.org/FAQHelp.html * * * *************************************************************************** http://www.FreeRTOS.org - Documentation, books, training, latest versions, license and Real Time Engineers Ltd. contact details. http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products, including FreeRTOS+Trace - an indispensable productivity tool, a DOS compatible FAT file system, and our tiny thread aware UDP/IP stack. http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS licenses offer ticketed support, indemnification and middleware. http://www.SafeRTOS.com - High Integrity Systems also provide a safety engineered and independently SIL3 certified version for use in safety and mission critical applications that require provable dependability. 1 tab == 4 spaces! */ /* Changes from V1.2.3 + The function xPortInitMinimal() has been renamed to xSerialPortInitMinimal() and the function xPortInit() has been renamed to xSerialPortInit(). Changes from V2.0.0 + Delay periods are now specified using variables and constants of portTickType rather than unsigned long. + xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR. Changes from V2.6.0 + Replaced the inb() and outb() functions with direct memory access. This allows the port to be built with the 20050414 build of WinAVR. */ /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */ #include #include #include "FreeRTOS.h" #include "queue.h" #include "task.h" #include "serial.h" #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 ) /* Constants for writing to UCSRB. */ #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 ) #define serRX_ENABLE ( ( unsigned char ) 0x10 ) #define serTX_ENABLE ( ( unsigned char ) 0x08 ) #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 ) /* Constants for writing to UCSRC. */ #define serUCSRC_SELECT ( ( unsigned char ) 0x80 ) #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 ) static xQueueHandle xRxedChars; static xQueueHandle xCharsForTx; #define vInterruptOn() \ { \ unsigned char ucByte; \ \ ucByte = UCSRB; \ ucByte |= serTX_INT_ENABLE; \ UCSRB = ucByte; \ } /*-----------------------------------------------------------*/ #define vInterruptOff() \ { \ unsigned char ucInByte; \ \ ucInByte = UCSRB; \ ucInByte &= ~serTX_INT_ENABLE; \ UCSRB = ucInByte; \ } /*-----------------------------------------------------------*/ xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) { unsigned long ulBaudRateCounter; unsigned char ucByte; portENTER_CRITICAL(); { /* Create the queues used by the com test task. */ xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); /* Calculate the baud rate register value from the equation in the data sheet. */ ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1; /* Set the baud rate. */ ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff ); UBRRL = ucByte; ulBaudRateCounter >>= ( unsigned long ) 8; ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff ); UBRRH = ucByte; /* Enable the Rx interrupt. The Tx interrupt will get enabled later. Also enable the Rx and Tx. */ UCSRB = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE ); /* Set the data bits to 8. */ UCSRC = ( serUCSRC_SELECT | serEIGHT_DATA_BITS ); } 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 char *pcRxedChar, portTickType xBlockTime ) { /* Only one port is supported. */ ( void ) pxPort; /* 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 char cOutChar, portTickType xBlockTime ) { /* Only one port is supported. */ ( void ) pxPort; /* Return false if after the block time there is no room on the Tx queue. */ if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS ) { return pdFAIL; } vInterruptOn(); return pdPASS; } /*-----------------------------------------------------------*/ void vSerialClose( xComPortHandle xPort ) { unsigned char ucByte; /* The parameter is not used. */ ( void ) xPort; /* Turn off the interrupts. We may also want to delete the queues and/or re-install the original ISR. */ portENTER_CRITICAL(); { vInterruptOff(); ucByte = UCSRB; ucByte &= ~serRX_INT_ENABLE; UCSRB = ucByte; } portEXIT_CRITICAL(); } /*-----------------------------------------------------------*/ SIGNAL( SIG_UART_RECV ) { signed char cChar; signed 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 = UDR; xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken ); if( xHigherPriorityTaskWoken != pdFALSE ) { taskYIELD(); } } /*-----------------------------------------------------------*/ SIGNAL( SIG_UART_DATA ) { signed char cChar, cTaskWoken; if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE ) { /* Send the next character queued for Tx. */ UDR = cChar; } else { /* Queue empty, nothing to send. */ vInterruptOff(); } }