2 FreeRTOS V7.1.1 - Copyright (C) 2012 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 >>>NOTE<<< The modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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68 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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71 /* Library includes. */
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76 /* Scheduler includes. */
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77 #include "FreeRTOS.h"
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80 /* Demo application includes. */
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83 #define UART0_Rx_Pin ( 0x0001<< 8 )
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84 #define UART0_Tx_Pin ( 0x0001<< 9 )
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86 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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87 #define serNO_BLOCK ( ( portTickType ) 0 )
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89 /* Macros to turn on and off the Tx empty interrupt. */
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90 #define serINTERRUPT_ON() UART0->IER |= UART_TxHalfEmpty
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91 #define serINTERRUPT_OFF() UART0->IER &= ~UART_TxHalfEmpty
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93 /*-----------------------------------------------------------*/
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95 /* Queues used to hold received characters, and characters waiting to be
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97 static xQueueHandle xRxedChars;
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98 static xQueueHandle xCharsForTx;
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100 /*-----------------------------------------------------------*/
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102 /* Interrupt entry point written in the assembler file serialISR.s79. */
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103 extern void vSerialISREntry( void );
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105 /* The interrupt service routine - called from the assembly entry point. */
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106 __arm void vSerialISR( void );
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108 /*-----------------------------------------------------------*/
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111 * See the serial2.h header file.
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113 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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115 xComPortHandle xReturn;
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117 /* Create the queues used to hold Rx and 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 portENTER_CRITICAL();
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127 /* Setup the UART port pins. */
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128 GPIO_Config( GPIO0, UART0_Tx_Pin, GPIO_AF_PP );
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129 GPIO_Config( GPIO0, UART0_Rx_Pin, GPIO_IN_TRI_CMOS );
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131 /* Configure the UART. */
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132 UART_OnOffConfig( UART0, ENABLE );
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133 UART_FifoConfig( UART0, DISABLE );
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134 UART_FifoReset( UART0, UART_RxFIFO );
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135 UART_FifoReset( UART0, UART_TxFIFO );
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136 UART_LoopBackConfig(UART0, DISABLE );
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137 UART_Config( UART0, ulWantedBaud, UART_NO_PARITY, UART_1_StopBits, UARTM_8D );
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138 UART_RxConfig( UART0, ENABLE );
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140 /* Configure the IEC for the UART interrupts. */
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141 EIC_IRQChannelPriorityConfig( UART0_IRQChannel, 1 );
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142 EIC_IRQChannelConfig( UART0_IRQChannel, ENABLE );
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143 EIC_IRQConfig( ENABLE );
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144 UART_ItConfig( UART0, UART_RxBufFull, ENABLE );
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146 portEXIT_CRITICAL();
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150 xReturn = ( xComPortHandle ) 0;
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153 /* This demo file only supports a single port but we have to return
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154 something to comply with the standard demo header file. */
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157 /*-----------------------------------------------------------*/
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159 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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161 /* The port handle is not required as this driver only supports one port. */
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164 /* Get the next character from the buffer. Return false if no characters
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165 are available, or arrive before xBlockTime expires. */
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166 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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175 /*-----------------------------------------------------------*/
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177 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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179 signed char *pxNext;
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181 /* A couple of parameters that this port does not use. */
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182 ( void ) usStringLength;
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185 /* NOTE: This implementation does not handle the queue being full as no
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186 block time is used! */
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188 /* The port handle is not required as this driver only supports UART0. */
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191 /* Send each character in the string, one at a time. */
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192 pxNext = ( signed char * ) pcString;
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195 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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199 /*-----------------------------------------------------------*/
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201 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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203 /* Place the character in the queue of characters to be transmitted. */
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204 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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209 /* Turn on the Tx interrupt so the ISR will remove the character from the
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210 queue and send it. This does not need to be in a critical section as
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211 if the interrupt has already removed the character the next interrupt
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212 will simply turn off the Tx interrupt again. */
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217 /*-----------------------------------------------------------*/
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219 void vSerialClose( xComPortHandle xPort )
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221 /* Not supported as not required by the demo application. */
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223 /*-----------------------------------------------------------*/
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225 /* Serial port ISR. This can cause a context switch so is not defined as a
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226 standard ISR using the __irq keyword. Instead a wrapper function is defined
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227 within serialISR.s79 which in turn calls this function. See the port
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228 documentation on the FreeRTOS.org website for more information. */
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229 __arm void vSerialISR( void )
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231 unsigned short usStatus;
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233 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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235 /* What caused the interrupt? */
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236 usStatus = UART_FlagStatus( UART0 );
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238 if( usStatus & UART_TxHalfEmpty )
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240 /* The interrupt was caused by the THR becoming empty. Are there any
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241 more characters to transmit? */
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242 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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244 /* A character was retrieved from the queue so can be sent to the
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246 UART0->TxBUFR = cChar;
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250 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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251 serINTERRUPT_OFF();
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255 if( usStatus & UART_RxBufFull )
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257 /* The interrupt was caused by a character being received. Grab the
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258 character from the RHR and place it in the queue of received
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260 cChar = UART0->RxBUFR;
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261 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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264 /* If a task was woken by either a character being received or a character
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265 being transmitted then we may need to switch to another task. */
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266 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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268 /* End the interrupt in the EIC. */
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