2 FreeRTOS V7.5.0 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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66 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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68 ***Note*** This example uses queues to send each character into an interrupt
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69 service routine and out of an interrupt service routine individually. This
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70 is done to demonstrate queues being used in an interrupt, and to deliberately
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71 load the system to test the FreeRTOS port. It is *NOT* meant to be an
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72 example of an efficient implementation. An efficient implementation should
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73 use FIFO's or DMA if available, and only use FreeRTOS API functions when
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74 enough has been received to warrant a task being unblocked to process the
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78 /* Scheduler includes. */
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79 #include "FreeRTOS.h"
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82 #include "comtest2.h"
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84 /* Library includes. */
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85 #include "stm32l152_eval.h"
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87 /* Demo application includes. */
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89 /*-----------------------------------------------------------*/
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92 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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93 #define serNO_BLOCK ( ( portTickType ) 0 )
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95 /*-----------------------------------------------------------*/
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97 /* The queue used to hold received characters. */
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98 static xQueueHandle xRxedChars;
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99 static xQueueHandle xCharsForTx;
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101 /*-----------------------------------------------------------*/
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104 * See the serial2.h header file.
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106 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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108 USART_InitTypeDef USART_InitStructure;
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109 xComPortHandle xReturn;
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110 NVIC_InitTypeDef NVIC_InitStructure;
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112 /* Create the queues used to hold Rx/Tx characters. */
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113 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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114 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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116 /* If the queues were created correctly then setup the serial port
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118 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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120 USART_InitStructure.USART_BaudRate = ulWantedBaud;
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121 USART_InitStructure.USART_WordLength = USART_WordLength_8b;
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122 USART_InitStructure.USART_StopBits = USART_StopBits_1;
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123 USART_InitStructure.USART_Parity = USART_Parity_No;
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124 USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
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125 USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
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127 /* The Eval board COM2 is being used, which in reality is the STM32
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129 STM_EVAL_COMInit( COM2, &USART_InitStructure );
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131 NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
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132 NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY;
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133 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0; /* Not used as 4 bits are used for the pre-emption priority. */;
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134 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
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135 NVIC_Init( &NVIC_InitStructure );
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136 USART_ITConfig( USART3, USART_IT_RXNE, ENABLE );
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140 xReturn = ( xComPortHandle ) 0;
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143 /* This demo file only supports a single port but we have to return
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144 something to comply with the standard demo header file. */
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147 /*-----------------------------------------------------------*/
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149 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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151 /* The port handle is not required as this driver only supports one port. */
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154 /* Get the next character from the buffer. Return false if no characters
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155 are available, or arrive before xBlockTime expires. */
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156 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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165 /*-----------------------------------------------------------*/
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167 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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169 signed portCHAR *pxNext;
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171 /* A couple of parameters that this port does not use. */
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172 ( void ) usStringLength;
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175 /* NOTE: This implementation does not handle the queue being full as no
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176 block time is used! */
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178 /* The port handle is not required as this driver only supports UART1. */
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181 /* Send each character in the string, one at a time. */
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182 pxNext = ( signed portCHAR * ) pcString;
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185 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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189 /*-----------------------------------------------------------*/
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191 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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193 signed portBASE_TYPE xReturn;
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195 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
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198 USART_ITConfig( USART3, USART_IT_TXE, ENABLE );
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207 /*-----------------------------------------------------------*/
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209 void vSerialClose( xComPortHandle xPort )
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211 /* Not supported as not required by the demo application. */
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213 /*-----------------------------------------------------------*/
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215 void USART3_IRQHandler( void )
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217 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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220 if( USART_GetITStatus( USART3, USART_IT_TXE ) == SET )
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222 /* The interrupt was caused by the TX register becoming empty. Are
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223 there any more characters to transmit? */
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224 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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226 /* A character was retrieved from the queue so can be sent to the
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228 USART_SendData( USART3, cChar );
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232 USART_ITConfig( USART3, USART_IT_TXE, DISABLE );
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236 if( USART_GetITStatus( USART3, USART_IT_RXNE ) == SET )
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238 /* A character has been received on the USART, send it to the Rx
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240 cChar = USART_ReceiveData( USART3 );
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241 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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244 /* If sending or receiving from a queue has caused a task to unblock, and
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245 the unblocked task has a priority equal to or higher than the currently
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246 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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247 will have automatically been set to pdTRUE within the queue send or receive
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248 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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249 directly to the higher priority unblocked task. */
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250 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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