/* 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! */ /* 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" /*-----------------------------------------------------------*/ /* Location of the COM0 registers. */ #define serCOM0 ( ( AT91PS_USART ) AT91C_BASE_US0 ) /* Interrupt control macros. */ #define serINTERRUPT_LEVEL ( 5 ) #define vInterruptOn() AT91F_US_EnableIt( serCOM0, AT91C_US_TXRDY | AT91C_US_RXRDY ) #define vInterruptOff() AT91F_US_DisableIt( serCOM0, 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; /*-----------------------------------------------------------*/ /* Interrupt entry point written in the assembler file serialISR.s79. */ extern void vSerialISREntry( void ); /* The interrupt service routine - called from the assembly entry point. */ __arm 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 ); /* 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 USART clock. */ AT91F_PMC_EnablePeriphClock( AT91C_BASE_PMC, 1 << AT91C_ID_US0 ); AT91F_PIO_CfgPeriph( AT91C_BASE_PIOA, ( ( unsigned long ) AT91C_PA5_RXD0 ) | ( ( unsigned long ) AT91C_PA6_TXD0 ), serNO_PERIPHERAL_B_SETUP ); /* Set the required protocol. */ AT91F_US_Configure( serCOM0, configCPU_CLOCK_HZ, AT91C_US_ASYNC_MODE, ulWantedBaud, serNO_TIMEGUARD ); /* Enable Rx and Tx. */ serCOM0->US_CR = AT91C_US_RXEN | AT91C_US_TXEN; /* Enable the Rx interrupts. The Tx interrupts are not enabled until there are characters to be transmitted. */ AT91F_US_EnableIt( serCOM0, AT91C_US_RXRDY ); /* Enable the interrupts in the AIC. */ AT91F_AIC_ConfigureIt( AT91C_BASE_AIC, AT91C_ID_US0, serINTERRUPT_LEVEL, AT91C_AIC_SRCTYPE_INT_LEVEL_SENSITIVE, ( void (*)( void ) ) vSerialISREntry ); AT91F_AIC_EnableIt( AT91C_BASE_AIC, AT91C_ID_US0 ); } 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. */ } /*-----------------------------------------------------------*/ /* Serial port ISR. This can cause a context switch so is not defined as a standard ISR using the __irq keyword. Instead a wrapper function is defined within serialISR.s79 which in turn calls this function. See the port documentation on the FreeRTOS.org website for more information. */ __arm void vSerialISR( void ) { unsigned long ulStatus; signed char cChar; portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE; /* What caused the interrupt? */ ulStatus = serCOM0->US_CSR &= serCOM0->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. */ serCOM0->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 = serCOM0->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 ); /* End the interrupt in the AIC. */ AT91C_BASE_AIC->AIC_EOICR = 0; }