229 lines
8.2 KiB
C
229 lines
8.2 KiB
C
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/*
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* FreeRTOS V202212.00
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* https://www.FreeRTOS.org
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* https://github.com/FreeRTOS
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*
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*/
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/*
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* A simple example that shows a stream buffer being used to pass data from an
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* interrupt to a task.
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*
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* There are two strings, pcStringToSend and pcStringToReceive, where
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* pcStringToReceive is a substring of pcStringToSend. The interrupt sends
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* a few bytes of pcStringToSend to a stream buffer ever few times that it
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* executes. A task reads the bytes from the stream buffer, looking for the
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* substring, and flagging an error if the received data is invalid.
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*/
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/* Standard includes. */
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#include "stdio.h"
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#include "string.h"
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/* FreeRTOS includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "stream_buffer.h"
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/* Demo app includes. */
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#include "StreamBufferInterrupt.h"
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#define sbiSTREAM_BUFFER_LENGTH_BYTES ( ( size_t ) 100 )
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#define sbiSTREAM_BUFFER_TRIGGER_LEVEL_10 ( ( BaseType_t ) 10 )
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/*-----------------------------------------------------------*/
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/* Implements the task that receives a stream of bytes from the interrupt. */
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static void prvReceivingTask( void * pvParameters );
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/*-----------------------------------------------------------*/
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/* The stream buffer that is used to send data from an interrupt to the task. */
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static StreamBufferHandle_t xStreamBuffer = NULL;
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/* The string that is sent from the interrupt to the task four bytes at a
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* time. Must be multiple of 4 bytes long as the ISR sends 4 bytes at a time*/
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static const char * pcStringToSend = "_____Hello FreeRTOS_____";
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/* The string to task is looking for, which must be a substring of
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* pcStringToSend. */
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static const char * pcStringToReceive = "Hello FreeRTOS";
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/* Set to pdFAIL if anything unexpected happens. */
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static BaseType_t xDemoStatus = pdPASS;
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/* Incremented each time pcStringToReceive is correctly received, provided no
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* errors have occurred. Used so the check task can check this task is still
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* running as expected. */
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static uint32_t ulCycleCount = 0;
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/*-----------------------------------------------------------*/
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void vStartStreamBufferInterruptDemo( void )
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{
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/* Create the stream buffer that sends data from the interrupt to the
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* task, and create the task. */
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xStreamBuffer = xStreamBufferCreate( /* The buffer length in bytes. */
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sbiSTREAM_BUFFER_LENGTH_BYTES,
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/* The stream buffer's trigger level. */
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sbiSTREAM_BUFFER_TRIGGER_LEVEL_10 );
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xTaskCreate( prvReceivingTask, /* The function that implements the task. */
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"StrIntRx", /* Human readable name for the task. */
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configMINIMAL_STACK_SIZE, /* Stack size (in words!). */
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NULL, /* Task parameter is not used. */
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tskIDLE_PRIORITY + 2, /* The priority at which the task is created. */
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NULL ); /* No use for the task handle. */
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}
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/*-----------------------------------------------------------*/
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static void prvReceivingTask( void * pvParameters )
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{
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char cRxBuffer[ 20 ];
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BaseType_t xNextByte = 0;
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/* Remove warning about unused parameters. */
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( void ) pvParameters;
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/* Make sure the string will fit in the Rx buffer, including the NULL
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* terminator. */
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configASSERT( sizeof( cRxBuffer ) > strlen( pcStringToReceive ) );
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/* Make sure the stream buffer has been created. */
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configASSERT( xStreamBuffer != NULL );
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/* Start with the Rx buffer in a known state. */
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memset( cRxBuffer, 0x00, sizeof( cRxBuffer ) );
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for( ; ; )
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{
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/* Keep receiving characters until the end of the string is received.
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* Note: An infinite block time is used to simplify the example. Infinite
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* block times are not recommended in production code as they do not allow
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* for error recovery. */
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xStreamBufferReceive( /* The stream buffer data is being received from. */
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xStreamBuffer,
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/* Where to place received data. */
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( void * ) &( cRxBuffer[ xNextByte ] ),
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/* The number of bytes to receive. */
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sizeof( char ),
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/* The time to wait for the next data if the buffer
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* is empty. */
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portMAX_DELAY );
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/* If xNextByte is 0 then this task is looking for the start of the
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* string, which is 'H'. */
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if( xNextByte == 0 )
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{
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if( cRxBuffer[ xNextByte ] == 'H' )
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{
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/* The start of the string has been found. Now receive
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* characters until the end of the string is found. */
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xNextByte++;
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}
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}
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else
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{
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/* Receiving characters while looking for the end of the string,
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* which is an 'S'. */
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if( cRxBuffer[ xNextByte ] == 'S' )
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{
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/* The string has now been received. Check its validity. */
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if( strcmp( cRxBuffer, pcStringToReceive ) != 0 )
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{
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xDemoStatus = pdFAIL;
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}
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/* Return to start looking for the beginning of the string
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* again. */
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memset( cRxBuffer, 0x00, sizeof( cRxBuffer ) );
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xNextByte = 0;
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/* Increment the cycle count as an indication to the check task
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* that this demo is still running. */
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if( xDemoStatus == pdPASS )
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{
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ulCycleCount++;
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}
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}
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else
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{
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/* Receive the next character the next time around, while
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* continuing to look for the end of the string. */
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xNextByte++;
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configASSERT( ( size_t ) xNextByte < sizeof( cRxBuffer ) );
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}
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}
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}
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}
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/*-----------------------------------------------------------*/
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void vBasicStreamBufferSendFromISR( void )
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{
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static size_t xNextByteToSend = 0;
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const BaseType_t xCallsBetweenSends = 100, xBytesToSend = 4;
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static BaseType_t xCallCount = 0;
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/* Is it time to write to the stream buffer again? */
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xCallCount++;
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if( xCallCount > xCallsBetweenSends )
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{
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xCallCount = 0;
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/* Send the next four bytes to the stream buffer. */
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xStreamBufferSendFromISR( xStreamBuffer,
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( const void * ) ( pcStringToSend + xNextByteToSend ),
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xBytesToSend,
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NULL );
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/* Send the next four bytes the next time around, wrapping to the start
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* of the string if necessary. */
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xNextByteToSend += xBytesToSend;
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if( xNextByteToSend >= strlen( pcStringToSend ) )
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{
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xNextByteToSend = 0;
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}
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}
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}
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/*-----------------------------------------------------------*/
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BaseType_t xIsInterruptStreamBufferDemoStillRunning( void )
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{
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uint32_t ulLastCycleCount = 0;
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/* Check the demo is still running. */
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if( ulLastCycleCount == ulCycleCount )
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{
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xDemoStatus = pdFAIL;
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}
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else
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{
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ulLastCycleCount = ulCycleCount;
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}
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return xDemoStatus;
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}
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