2 FreeRTOS V9.0.0rc2 - Copyright (C) 2016 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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71 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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73 ***Note*** This example uses queues to send each character into an interrupt
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74 service routine and out of an interrupt service routine individually. This
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75 is done to demonstrate queues being used in an interrupt, and to deliberately
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76 load the system to test the FreeRTOS port. It is *NOT* meant to be an
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77 example of an efficient implementation. An efficient implementation should
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78 use FIFO's or DMA if available, and only use FreeRTOS API functions when
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79 enough has been received to warrant a task being unblocked to process the
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83 /* Scheduler includes. */
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84 #include "FreeRTOS.h"
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87 #include "comtest2.h"
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89 /* Library includes. */
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90 #include "stm32l152_eval.h"
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92 /* Demo application includes. */
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94 /*-----------------------------------------------------------*/
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97 #define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
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98 #define serNO_BLOCK ( ( TickType_t ) 0 )
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100 /*-----------------------------------------------------------*/
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102 /* The queue used to hold received characters. */
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103 static QueueHandle_t xRxedChars;
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104 static QueueHandle_t xCharsForTx;
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106 /*-----------------------------------------------------------*/
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109 * See the serial2.h header file.
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111 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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113 USART_InitTypeDef USART_InitStructure;
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114 xComPortHandle xReturn;
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115 NVIC_InitTypeDef NVIC_InitStructure;
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117 /* Create the queues used to hold Rx/Tx characters. */
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118 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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119 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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121 /* If the queues were created correctly then setup the serial port
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123 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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125 USART_InitStructure.USART_BaudRate = ulWantedBaud;
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126 USART_InitStructure.USART_WordLength = USART_WordLength_8b;
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127 USART_InitStructure.USART_StopBits = USART_StopBits_1;
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128 USART_InitStructure.USART_Parity = USART_Parity_No;
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129 USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
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130 USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
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132 /* The Eval board COM2 is being used, which in reality is the STM32
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134 STM_EVAL_COMInit( COM2, &USART_InitStructure );
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136 NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
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137 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY;
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138 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; /* Not used as 4 bits are used for the pre-emption priority. */;
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139 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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140 NVIC_Init( &NVIC_InitStructure );
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141 USART_ITConfig( USART3, USART_IT_RXNE, ENABLE );
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145 xReturn = ( xComPortHandle ) 0;
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148 /* This demo file only supports a single port but we have to return
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149 something to comply with the standard demo header file. */
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152 /*-----------------------------------------------------------*/
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154 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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156 /* The port handle is not required as this driver only supports one port. */
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159 /* Get the next character from the buffer. Return false if no characters
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160 are available, or arrive before xBlockTime expires. */
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161 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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170 /*-----------------------------------------------------------*/
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172 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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174 signed char *pxNext;
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176 /* A couple of parameters that this port does not use. */
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177 ( void ) usStringLength;
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180 /* NOTE: This implementation does not handle the queue being full as no
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181 block time is used! */
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183 /* The port handle is not required as this driver only supports UART1. */
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186 /* Send each character in the string, one at a time. */
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187 pxNext = ( signed char * ) pcString;
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190 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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194 /*-----------------------------------------------------------*/
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196 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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198 signed portBASE_TYPE xReturn;
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200 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
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203 USART_ITConfig( USART3, USART_IT_TXE, ENABLE );
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212 /*-----------------------------------------------------------*/
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214 void vSerialClose( xComPortHandle xPort )
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216 /* Not supported as not required by the demo application. */
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218 /*-----------------------------------------------------------*/
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220 void USART3_IRQHandler( void )
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222 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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225 if( USART_GetITStatus( USART3, USART_IT_TXE ) == SET )
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227 /* The interrupt was caused by the TX register becoming empty. Are
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228 there any more characters to transmit? */
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229 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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231 /* A character was retrieved from the queue so can be sent to the
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233 USART_SendData( USART3, cChar );
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237 USART_ITConfig( USART3, USART_IT_TXE, DISABLE );
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241 if( USART_GetITStatus( USART3, USART_IT_RXNE ) == SET )
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243 /* A character has been received on the USART, send it to the Rx
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245 cChar = USART_ReceiveData( USART3 );
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246 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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249 /* If sending or receiving from a queue has caused a task to unblock, and
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250 the unblocked task has a priority equal to or higher than the currently
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251 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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252 will have automatically been set to pdTRUE within the queue send or receive
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253 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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254 directly to the higher priority unblocked task. */
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255 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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