2 FreeRTOS V8.2.0rc1 - Copyright (C) 2014 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 >>! NOTE: The modification to the GPL is included to allow you to !<<
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14 >>! distribute a combined work that includes FreeRTOS without being !<<
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15 >>! obliged to provide the source code for proprietary components !<<
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16 >>! outside of the FreeRTOS kernel. !<<
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18 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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19 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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20 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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21 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * Having a problem? Start by reading the FAQ "My application does *
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28 * not run, what could be wrong?". Have you defined configASSERT()? *
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30 * http://www.FreeRTOS.org/FAQHelp.html *
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32 ***************************************************************************
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34 ***************************************************************************
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36 * FreeRTOS provides completely free yet professionally developed, *
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37 * robust, strictly quality controlled, supported, and cross *
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38 * platform software that is more than just the market leader, it *
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39 * is the industry's de facto standard. *
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41 * Help yourself get started quickly while simultaneously helping *
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42 * to support the FreeRTOS project by purchasing a FreeRTOS *
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43 * tutorial book, reference manual, or both: *
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44 * http://www.FreeRTOS.org/Documentation *
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46 ***************************************************************************
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48 ***************************************************************************
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50 * Investing in training allows your team to be as productive as *
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51 * possible as early as possible, lowering your overall development *
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52 * cost, and enabling you to bring a more robust product to market *
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53 * earlier than would otherwise be possible. Richard Barry is both *
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54 * the architect and key author of FreeRTOS, and so also the world's *
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55 * leading authority on what is the world's most popular real time *
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56 * kernel for deeply embedded MCU designs. Obtaining your training *
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57 * from Richard ensures your team will gain directly from his in-depth *
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58 * product knowledge and years of usage experience. Contact Real Time *
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59 * Engineers Ltd to enquire about the FreeRTOS Masterclass, presented *
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60 * by Richard Barry: http://www.FreeRTOS.org/contact
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62 ***************************************************************************
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64 ***************************************************************************
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66 * You are receiving this top quality software for free. Please play *
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67 * fair and reciprocate by reporting any suspected issues and *
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68 * participating in the community forum: *
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69 * http://www.FreeRTOS.org/support *
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73 ***************************************************************************
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75 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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76 license and Real Time Engineers Ltd. contact details.
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78 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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79 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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80 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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82 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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83 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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85 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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86 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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87 licenses offer ticketed support, indemnification and commercial middleware.
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89 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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90 engineered and independently SIL3 certified version for use in safety and
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91 mission critical applications that require provable dependability.
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97 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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99 * This is not a proper UART driver. It only supports one port, uses loopback
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100 * mode, and is used to test interrupts that use the FreeRTOS API as part of
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101 * a wider test suite. Nor is it intended to show an efficient implementation
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102 * of a UART interrupt service routine as queues are used to pass individual
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103 * characters one at a time!
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106 /* Standard includes. */
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107 #include <stdlib.h>
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109 /* Scheduler includes. */
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110 #include "FreeRTOS.h"
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114 /* Demo application includes. */
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115 #include "serial.h"
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117 /* Misc. constants. */
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118 #define serNO_BLOCK ( ( TickType_t ) 0 )
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120 /* The queue used to hold received characters. */
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121 static QueueHandle_t xRxedChars;
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123 /* The queue used to hold characters waiting transmission. */
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124 static QueueHandle_t xCharsForTx;
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126 /*-----------------------------------------------------------*/
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128 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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130 unsigned long ulBaudRateCount;
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132 /* Initialise the hardware. */
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134 /* Generate the baud rate constants for the wanted baud rate. */
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135 ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;
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137 portENTER_CRITICAL();
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139 /* Create the queues used by the com test task. */
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140 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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141 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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144 UCA1CTL1 |= UCSWRST;
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147 UCA1CTL1 = UCSSEL0 | UCSSEL1;
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149 /* Setup baud rate low byte. */
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150 UCA1BR0 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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152 /* Setup baud rate high byte. */
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153 ulBaudRateCount >>= 8UL;
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154 UCA1BR1 = ( unsigned char ) ( ulBaudRateCount & ( unsigned long ) 0xff );
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156 /* UCLISTEN sets loopback mode! */
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157 UCA1STAT = UCLISTEN;
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159 /* Enable interrupts. */
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162 /* Take out of reset. */
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163 UCA1CTL1 &= ~UCSWRST;
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165 portEXIT_CRITICAL();
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167 /* Note the comments at the top of this file about this not being a generic
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171 /*-----------------------------------------------------------*/
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173 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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175 /* Get the next character from the buffer. Return false if no characters
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176 are available, or arrive before xBlockTime expires. */
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177 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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186 /*-----------------------------------------------------------*/
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188 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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190 signed portBASE_TYPE xReturn;
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192 /* Send the next character to the queue of characters waiting transmission,
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193 then enable the UART Tx interrupt, just in case UART transmission has already
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194 completed and switched itself off. */
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195 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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200 /*-----------------------------------------------------------*/
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202 /* The implementation of this interrupt is provided to demonstrate the use
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203 of queues from inside an interrupt service routine. It is *not* intended to
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204 be an efficient interrupt implementation. A real application should make use
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205 of the DMA. Or, as a minimum, transmission and reception could use a simple
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206 RAM ring buffer, and synchronise with a task using a semaphore when a complete
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207 message has been received or transmitted. */
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208 #pragma vector=USCI_A1_VECTOR
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209 static __interrupt void prvUSCI_A1_ISR( void )
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212 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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214 while( ( UCA1IFG & UCRXIFG ) != 0 )
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216 /* Get the character from the UART and post it on the queue of Rxed
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219 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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222 /* If there is a Tx interrupt pending and the tx interrupts are enabled. */
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223 if( ( UCA1IFG & UCTXIFG ) != 0 )
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225 /* The previous character has been transmitted. See if there are any
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226 further characters waiting transmission. */
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227 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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229 /* There was another character queued - transmit it now. */
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234 /* There were no other characters to transmit - disable the Tx
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240 __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
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242 /* If writing to a queue caused a task to unblock, and the unblocked task
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243 has a priority equal to or above the task that this interrupt interrupted,
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244 then lHigherPriorityTaskWoken will have been set to pdTRUE internally within
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245 xQueuesendFromISR(), and portEND_SWITCHING_ISR() will ensure that this
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246 interrupt returns directly to the higher priority unblocked task.
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248 THIS MUST BE THE LAST THING DONE IN THE ISR. */
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249 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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