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updated usart code
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John Cobb
278
Drivers/serial.c
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278
Drivers/serial.c
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/*
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FreeRTOS V8.2.0 - Copyright (C) 2015 Real Time Engineers Ltd.
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All rights reserved
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VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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This file is part of the FreeRTOS distribution.
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FreeRTOS is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License (version 2) as published by the
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Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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***************************************************************************
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>>! NOTE: The modification to the GPL is included to allow you to !<<
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>>! distribute a combined work that includes FreeRTOS without being !<<
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>>! obliged to provide the source code for proprietary components !<<
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>>! outside of the FreeRTOS kernel. !<<
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***************************************************************************
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. Full license text is available on the following
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link: http://www.freertos.org/a00114.html
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***************************************************************************
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* *
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* FreeRTOS provides completely free yet professionally developed, *
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* robust, strictly quality controlled, supported, and cross *
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* platform software that is more than just the market leader, it *
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* is the industry's de facto standard. *
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* *
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* Help yourself get started quickly while simultaneously helping *
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* to support the FreeRTOS project by purchasing a FreeRTOS *
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* tutorial book, reference manual, or both: *
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* http://www.FreeRTOS.org/Documentation *
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* *
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***************************************************************************
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http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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the FAQ page "My application does not run, what could be wrong?". Have you
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defined configASSERT()?
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http://www.FreeRTOS.org/support - In return for receiving this top quality
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embedded software for free we request you assist our global community by
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participating in the support forum.
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http://www.FreeRTOS.org/training - Investing in training allows your team to
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be as productive as possible as early as possible. Now you can receive
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FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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Ltd, and the world's leading authority on the world's leading RTOS.
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http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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compatible FAT file system, and our tiny thread aware UDP/IP stack.
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http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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licenses offer ticketed support, indemnification and commercial middleware.
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http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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engineered and independently SIL3 certified version for use in safety and
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mission critical applications that require provable dependability.
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1 tab == 4 spaces!
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*/
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/*
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Changes from V1.2.3
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+ The function xPortInitMinimal() has been renamed to
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xSerialPortInitMinimal() and the function xPortInit() has been renamed
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to xSerialPortInit().
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Changes from V2.0.0
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+ Delay periods are now specified using variables and constants of
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TickType_t rather than unsigned long.
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+ xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR.
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Changes from V2.6.0
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+ Replaced the inb() and outb() functions with direct memory
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access. This allows the port to be built with the 20050414 build of
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WinAVR.
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*/
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/* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
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#include <stdlib.h>
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#include <avr/interrupt.h>
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#include "FreeRTOS.h"
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#include "queue.h"
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#include "task.h"
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#include "serial.h"
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#define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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/* Constants for writing to UCSRB. */
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//#define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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//#define serRX_ENABLE ( ( unsigned char ) 0x10 )
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//#define serTX_ENABLE ( ( unsigned char ) 0x08 )
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//#define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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#define serRX_INT_ENABLE _BV(RXCIE0)
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#define serRX_ENABLE _BV(RXEN0)
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#define serTX_ENABLE _BV(TXEN0)
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#define serTX_INT_ENABLE _BV(UDRIE0)
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/* Constants for writing to UCSRC. */
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//#define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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//#define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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#define serUCSRC_SELECT _BV(UCSZ00)
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#define serEIGHT_DATA_BITS _BV(UCSZ01)
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static QueueHandle_t xRxedChars;
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static QueueHandle_t xCharsForTx;
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#define vInterruptOn() \
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{ \
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unsigned char ucByte; \
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\
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ucByte = UCSR0B; \
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ucByte |= serTX_INT_ENABLE; \
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UCSR0B = ucByte; \
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}
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/*-----------------------------------------------------------*/
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#define vInterruptOff() \
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{ \
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unsigned char ucInByte; \
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\
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ucInByte = UCSR0B; \
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ucInByte &= ~serTX_INT_ENABLE; \
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UCSR0B = ucInByte; \
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}
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/*-----------------------------------------------------------*/
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xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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{
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unsigned long ulBaudRateCounter;
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unsigned char ucByte;
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portENTER_CRITICAL();
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{
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/* Create the queues used by the com test task. */
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xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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/* Calculate the baud rate register value from the equation in the
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data sheet. */
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ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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/* Set the baud rate. */
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ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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UBRR0L = ucByte;
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ulBaudRateCounter >>= ( unsigned long ) 8;
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ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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UBRR0H = ucByte;
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/* Enable the Rx interrupt. The Tx interrupt will get enabled
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later. Also enable the Rx and Tx. */
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UCSR0B = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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/* Set the data bits to 8. */
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UCSR0C = ( serUCSRC_SELECT | serEIGHT_DATA_BITS );
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}
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portEXIT_CRITICAL();
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/* Unlike other ports, this serial code does not allow for more than one
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com port. We therefore don't return a pointer to a port structure and can
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instead just return NULL. */
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return NULL;
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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{
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/* Only one port is supported. */
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( void ) pxPort;
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/* Get the next character from the buffer. Return false if no characters
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are available, or arrive before xBlockTime expires. */
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if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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{
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return pdTRUE;
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}
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else
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{
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return pdFALSE;
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}
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}
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/*-----------------------------------------------------------*/
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signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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{
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/* Only one port is supported. */
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( void ) pxPort;
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/* Return false if after the block time there is no room on the Tx queue. */
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if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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{
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return pdFAIL;
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}
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vInterruptOn();
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return pdPASS;
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}
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/*-----------------------------------------------------------*/
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void vSerialClose( xComPortHandle xPort )
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{
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unsigned char ucByte;
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/* The parameter is not used. */
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( void ) xPort;
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/* Turn off the interrupts. We may also want to delete the queues and/or
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re-install the original ISR. */
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portENTER_CRITICAL();
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{
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vInterruptOff();
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ucByte = UCSR0B;
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ucByte &= ~serRX_INT_ENABLE;
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UCSR0B = ucByte;
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}
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portEXIT_CRITICAL();
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}
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// http://www.nongnu.org/avr-libc/user-manual/group__avr__interrupts.html
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/*-----------------------------------------------------------*/
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// USART, Rx Complete
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//SIGNAL( SIG_UART_RECV )
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ISR(USART_RX_vect)
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{
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signed char cChar;
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signed portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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/* Get the character and post it on the queue of Rxed characters.
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If the post causes a task to wake force a context switch as the woken task
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may have a higher priority than the task we have interrupted. */
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cChar = UDR0;
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xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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if( xHigherPriorityTaskWoken != pdFALSE )
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{
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taskYIELD();
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}
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}
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/*-----------------------------------------------------------*/
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// USART Data Register Empty
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// SIGNAL( SIG_UART_DATA )
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ISR(USART_UDRE_vect)
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{
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signed char cChar, cTaskWoken;
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if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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{
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/* Send the next character queued for Tx. */
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UDR0 = cChar;
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}
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else
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{
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/* Queue empty, nothing to send. */
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vInterruptOff();
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}
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}
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