/* FreeRTOS V9.0.0rc1 - Copyright (C) 2016 Real Time Engineers Ltd. All rights reserved VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION. 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 on the following link: http://www.freertos.org/a00114.html *************************************************************************** * * * FreeRTOS provides completely free yet professionally developed, * * robust, strictly quality controlled, supported, and cross * * platform software that is more than just the market leader, it * * is the industry's de facto standard. * * * * Help yourself get started quickly while simultaneously helping * * to support the FreeRTOS project by purchasing a FreeRTOS * * tutorial book, reference manual, or both: * * http://www.FreeRTOS.org/Documentation * * * *************************************************************************** http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading the FAQ page "My application does not run, what could be wrong?". Have you defined configASSERT()? http://www.FreeRTOS.org/support - In return for receiving this top quality embedded software for free we request you assist our global community by participating in the support forum. http://www.FreeRTOS.org/training - Investing in training allows your team to be as productive as possible as early as possible. Now you can receive FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers Ltd, and the world's leading authority on the world's leading RTOS. 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.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate. Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS. http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS licenses offer ticketed support, indemnification and commercial 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! */ /* * Creates a task and a timer that operate on an interrupt driven serial port. * This demo assumes that the characters transmitted on a port will also be * received on the same port. Therefore, the UART must either be connected to * an echo server, or the uart connector must have a loopback connector fitted. * See http://www.serialporttool.com/CommEcho.htm for a suitable echo server * for Windows hosts. * * The timer sends a string to the UART, toggles an LED, then resets itself by * changing its own period. The period is calculated as a pseudo random number * between comTX_MAX_BLOCK_TIME and comTX_MIN_BLOCK_TIME. * * The task blocks on an Rx queue waiting for a character to become available. * Received characters are checked to ensure they match those transmitted by the * Tx timer. An error is latched if characters are missing, incorrect, or * arrive too slowly. * * How characters are actually transmitted and received is port specific. Demos * that include this test/demo file will provide example drivers. The Tx timer * executes in the context of the timer service (daemon) task, and must * therefore never attempt to block. * */ /* Scheduler include files. */ #include #include #include "FreeRTOS.h" #include "task.h" #include "timers.h" #ifndef configUSE_TIMERS #error This demo uses timers. configUSE_TIMERS must be set to 1 in FreeRTOSConfig.h. #endif #if configUSE_TIMERS != 1 #error This demo uses timers. configUSE_TIMERS must be set to 1 in FreeRTOSConfig.h. #endif /* Demo program include files. */ #include "serial.h" #include "comtest_strings.h" #include "partest.h" /* The size of the stack given to the Rx task. */ #define comSTACK_SIZE configMINIMAL_STACK_SIZE /* See the comment above the declaraction of the uxBaseLED variable. */ #define comTX_LED_OFFSET ( 0 ) #define comRX_LED_OFFSET ( 1 ) /* The Tx timer transmits the sequence of characters at a pseudo random interval that is capped between comTX_MAX_BLOCK_TIME and comTX_MIN_BLOCK_TIME. */ #define comTX_MAX_BLOCK_TIME ( ( TickType_t ) 0x96 ) #define comTX_MIN_BLOCK_TIME ( ( TickType_t ) 0x32 ) #define comOFFSET_TIME ( ( TickType_t ) 3 ) /* States for the simple state machine implemented in the Rx task. */ #define comtstWAITING_START_OF_STRING 0 #define comtstWAITING_END_OF_STRING 1 /* A short delay in ticks - this delay is used to allow the Rx queue to fill up a bit so more than one character can be processed at a time. This is relative to comTX_MIN_BLOCK_TIME to ensure it is never longer than the shortest gap between transmissions. It could be worked out more scientifically from the baud rate being used. */ #define comSHORT_DELAY ( comTX_MIN_BLOCK_TIME >> ( TickType_t ) 2 ) /* The string that is transmitted and received. */ #define comTRANSACTED_STRING "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890" /* A block time of 0 simply means "don't block". */ #define comtstDONT_BLOCK ( TickType_t ) 0 /* Handle to the com port used by both tasks. */ static xComPortHandle xPort = NULL; /* The callback function allocated to the transmit timer, as described in the comments at the top of this file. */ static void prvComTxTimerCallback( TimerHandle_t xTimer ); /* The receive task as described in the comments at the top of this file. */ static void vComRxTask( void *pvParameters ); /* The Rx task will toggle LED ( uxBaseLED + comRX_LED_OFFSET). The Tx task will toggle LED ( uxBaseLED + comTX_LED_OFFSET ). */ static UBaseType_t uxBaseLED = 0; /* The Rx task toggles uxRxLoops on each successful iteration of its defined function - provided no errors have ever been latched. If this variable stops incrementing, then an error has occurred. */ static volatile UBaseType_t uxRxLoops = 0UL; /* The timer used to periodically transmit the string. This is the timer that has prvComTxTimerCallback allocated to it as its callback function. */ static TimerHandle_t xTxTimer = NULL; /* The string length is held at file scope so the Tx timer does not need to calculate it each time it executes. */ static size_t xStringLength = 0U; /*-----------------------------------------------------------*/ void vStartComTestStringsTasks( UBaseType_t uxPriority, uint32_t ulBaudRate, UBaseType_t uxLED ) { /* Store values that are used at run time. */ uxBaseLED = uxLED; /* Calculate the string length here, rather than each time the Tx timer executes. */ xStringLength = strlen( comTRANSACTED_STRING ); /* Include the null terminator in the string length as this is used to detect the end of the string in the Rx task. */ xStringLength++; /* Initialise the com port, then spawn the Rx task and create the Tx timer. */ xSerialPortInitMinimal( ulBaudRate, ( xStringLength * 2U ) ); /* Create the Rx task and the Tx timer. The timer is started from the Rx task. */ xTaskCreate( vComRxTask, "COMRx", comSTACK_SIZE, NULL, uxPriority, ( TaskHandle_t * ) NULL ); xTxTimer = xTimerCreate( "TxTimer", comTX_MIN_BLOCK_TIME, pdFALSE, NULL, prvComTxTimerCallback ); configASSERT( xTxTimer ); } /*-----------------------------------------------------------*/ static void prvComTxTimerCallback( TimerHandle_t xTimer ) { TickType_t xTimeToWait; /* The parameter is not used in this case. */ ( void ) xTimer; /* Send the string. How this is actually performed depends on the sample driver provided with this demo. However - as this is a timer, it executes in the context of the timer task and therefore must not block. */ vSerialPutString( xPort, comTRANSACTED_STRING, xStringLength ); /* Toggle an LED to give a visible indication that another transmission has been performed. */ vParTestToggleLED( uxBaseLED + comTX_LED_OFFSET ); /* Wait a pseudo random time before sending the string again. */ xTimeToWait = xTaskGetTickCount() + comOFFSET_TIME; /* Ensure the time to wait is not greater than comTX_MAX_BLOCK_TIME. */ xTimeToWait %= comTX_MAX_BLOCK_TIME; /* Ensure the time to wait is not less than comTX_MIN_BLOCK_TIME. */ if( xTimeToWait < comTX_MIN_BLOCK_TIME ) { xTimeToWait = comTX_MIN_BLOCK_TIME; } /* Reset the timer to run again xTimeToWait ticks from now. This function is called from the context of the timer task, so the block time must not be anything other than zero. */ xTimerChangePeriod( xTxTimer, xTimeToWait, comtstDONT_BLOCK ); } /*-----------------------------------------------------------*/ static void vComRxTask( void *pvParameters ) { BaseType_t xState = comtstWAITING_START_OF_STRING, xErrorOccurred = pdFALSE; char *pcExpectedByte, cRxedChar; const xComPortHandle xPort = NULL; /* The parameter is not used in this example. */ ( void ) pvParameters; /* Start the Tx timer. This only needs to be started once, as it will reset itself thereafter. */ xTimerStart( xTxTimer, portMAX_DELAY ); /* The first expected Rx character is the first in the string that is transmitted. */ pcExpectedByte = comTRANSACTED_STRING; for( ;; ) { /* Wait for the next character. */ if( xSerialGetChar( xPort, &cRxedChar, ( comTX_MAX_BLOCK_TIME * 2 ) ) == pdFALSE ) { /* A character definitely should have been received by now. As a character was not received an error must have occurred (which might just be that the loopback connector is not fitted). */ xErrorOccurred = pdTRUE; } switch( xState ) { case comtstWAITING_START_OF_STRING: if( cRxedChar == *pcExpectedByte ) { /* The received character was the first character of the string. Move to the next state to check each character as it comes in until the entire string has been received. */ xState = comtstWAITING_END_OF_STRING; pcExpectedByte++; /* Block for a short period. This just allows the Rx queue to contain more than one character, and therefore prevent thrashing reads to the queue, and repetitive context switches as each character is received. */ vTaskDelay( comSHORT_DELAY ); } break; case comtstWAITING_END_OF_STRING: if( cRxedChar == *pcExpectedByte ) { /* The received character was the expected character. Was it the last character in the string - i.e. the null terminator? */ if( cRxedChar == 0x00 ) { /* The entire string has been received. If no errors have been latched, then increment the loop counter to show this task is still healthy. */ if( xErrorOccurred == pdFALSE ) { uxRxLoops++; /* Toggle an LED to give a visible sign that a complete string has been received. */ vParTestToggleLED( uxBaseLED + comRX_LED_OFFSET ); } /* Go back to wait for the start of the next string. */ pcExpectedByte = comTRANSACTED_STRING; xState = comtstWAITING_START_OF_STRING; } else { /* Wait for the next character in the string. */ pcExpectedByte++; } } else { /* The character received was not that expected. */ xErrorOccurred = pdTRUE; } break; default: /* Should not get here. Stop the Rx loop counter from incrementing to latch the error. */ xErrorOccurred = pdTRUE; break; } } } /*-----------------------------------------------------------*/ BaseType_t xAreComTestTasksStillRunning( void ) { BaseType_t xReturn; /* If the count of successful reception loops has not changed than at some time an error occurred (i.e. a character was received out of sequence) and false is returned. */ if( uxRxLoops == 0UL ) { xReturn = pdFALSE; } else { xReturn = pdTRUE; } /* Reset the count of successful Rx loops. When this function is called again it should have been incremented again. */ uxRxLoops = 0UL; return xReturn; }