/* FreeRTOS V7.4.2 - Copyright (C) 2013 Real Time Engineers Ltd. FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. *************************************************************************** * * * FreeRTOS tutorial books are available in pdf and paperback. * * Complete, revised, and edited pdf reference manuals are also * * available. * * * * Purchasing FreeRTOS documentation will not only help you, by * * ensuring you get running as quickly as possible and with an * * in-depth knowledge of how to use FreeRTOS, it will also help * * the FreeRTOS project to continue with its mission of providing * * professional grade, cross platform, de facto standard solutions * * for microcontrollers - completely free of charge! * * * * >>> See http://www.FreeRTOS.org/Documentation for details. <<< * * * * Thank you for using FreeRTOS, and 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 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. 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 Real Time Engineers Ltd., contact details for whom are available on the FreeRTOS WEB site. 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, and our new fully thread aware and reentrant UDP/IP stack. http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell the code with commercial support, indemnification and middleware, under the OpenRTOS brand. 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. */ /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0. */ /* Standard includes. */ #include /* Scheduler includes. */ #include "FreeRTOS.h" #include "queue.h" /* Demo application includes. */ #include "serial.h" /* Library includes. */ #include "usart/usart.h" #include "pmc/pmc.h" #include "irq/irq.h" #include "pio/pio.h" /*-----------------------------------------------------------*/ /* Interrupt control macros. */ #define serINTERRUPT_LEVEL ( 5 ) #define vInterruptOn() BOARD_USART_BASE->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY ) #define vInterruptOff() BOARD_USART_BASE->US_IDR = AT91C_US_TXRDY /* Misc constants. */ #define serINVALID_QUEUE ( ( xQueueHandle ) 0 ) #define serHANDLE ( ( xComPortHandle ) 1 ) #define serNO_BLOCK ( ( portTickType ) 0 ) #define serNO_TIMEGUARD ( ( unsigned long ) 0 ) #define serNO_PERIPHERAL_B_SETUP ( ( unsigned long ) 0 ) /* Queues used to hold received characters, and characters waiting to be transmitted. */ static xQueueHandle xRxedChars; static xQueueHandle xCharsForTx; /*-----------------------------------------------------------*/ /* The interrupt service routine - called from the assembly entry point. */ void vSerialISR( void ); /*-----------------------------------------------------------*/ /* * See the serial2.h header file. */ xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength ) { xComPortHandle xReturn = serHANDLE; extern void ( vUART_ISR )( void ); const Pin xUSART_Pins[] = { BOARD_PIN_USART_RXD, BOARD_PIN_USART_TXD }; /* Create the queues used to hold Rx and Tx characters. */ xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) ); /* If the queues were created correctly then setup the serial port hardware. */ if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) ) { portENTER_CRITICAL(); { /* Enable the peripheral clock in the PMC. */ PMC_EnablePeripheral( BOARD_ID_USART ); /* Configure the USART. */ USART_Configure( BOARD_USART_BASE, AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE | AT91C_US_NBSTOP_1_BIT, ulWantedBaud, configCPU_CLOCK_HZ ); /* Configure the interrupt. Note the pre-emption priority is set in bits [8:15] of the priority value passed as the parameter. */ IRQ_ConfigureIT( BOARD_ID_USART, ( configMAX_SYSCALL_INTERRUPT_PRIORITY << 8 ), vSerialISR ); IRQ_EnableIT( BOARD_ID_USART ); /* Enable receiver & transmitter. */ USART_SetTransmitterEnabled( BOARD_USART_BASE, pdTRUE ); USART_SetReceiverEnabled( BOARD_USART_BASE, pdTRUE ); /* Configure IO for USART use. */ PIO_Configure( xUSART_Pins, PIO_LISTSIZE( xUSART_Pins ) ); } portEXIT_CRITICAL(); } else { xReturn = ( xComPortHandle ) 0; } /* This demo file only supports a single port but we have to return something to comply with the standard demo header file. */ return xReturn; } /*-----------------------------------------------------------*/ signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime ) { /* The port handle is not required as this driver only supports one port. */ ( 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; } } /*-----------------------------------------------------------*/ void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength ) { signed char *pxNext; /* A couple of parameters that this port does not use. */ ( void ) usStringLength; ( void ) pxPort; /* NOTE: This implementation does not handle the queue being full as no block time is used! */ /* The port handle is not required as this driver only supports UART0. */ ( void ) pxPort; /* Send each character in the string, one at a time. */ pxNext = ( signed char * ) pcString; while( *pxNext ) { xSerialPutChar( pxPort, *pxNext, serNO_BLOCK ); pxNext++; } } /*-----------------------------------------------------------*/ signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime ) { /* Place the character in the queue of characters to be transmitted. */ if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS ) { return pdFAIL; } /* 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. */ vInterruptOn(); return pdPASS; } /*-----------------------------------------------------------*/ void vSerialClose( xComPortHandle xPort ) { /* Not supported as not required by the demo application. */ } /*-----------------------------------------------------------*/ void vSerialISR( void ) { unsigned long ulStatus; signed char cChar; portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; /* What caused the interrupt? */ ulStatus = BOARD_USART_BASE->US_CSR &= BOARD_USART_BASE->US_IMR; if( ulStatus & AT91C_US_TXRDY ) { /* The interrupt was caused by the THR becoming empty. Are there any more characters to transmit? */ if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE ) { /* A character was retrieved from the queue so can be sent to the THR now. */ BOARD_USART_BASE->US_THR = cChar; } else { /* Queue empty, nothing to send so turn off the Tx interrupt. */ vInterruptOff(); } } if( ulStatus & AT91C_US_RXRDY ) { /* The interrupt was caused by a character being received. Grab the character from the RHR and place it in the queue or received characters. */ cChar = BOARD_USART_BASE->US_RHR; xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken ); } /* If a task was woken by either a character being received or a character being transmitted then we may need to switch to another task. */ portEND_SWITCHING_ISR( xHigherPriorityTaskWoken ); }