2 FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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32 >>>NOTE<<< The modification to the GPL is included to allow you to
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33 distribute a combined work that includes FreeRTOS without being obliged to
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34 provide the source code for proprietary components outside of the FreeRTOS
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35 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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36 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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37 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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38 more details. You should have received a copy of the GNU General Public
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39 License and the FreeRTOS license exception along with FreeRTOS; if not it
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40 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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41 by writing to Richard Barry, contact details for whom are available on the
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46 ***************************************************************************
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48 * Having a problem? Start by reading the FAQ "My application does *
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49 * not run, what could be wrong?" *
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51 * http://www.FreeRTOS.org/FAQHelp.html *
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53 ***************************************************************************
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56 http://www.FreeRTOS.org - Documentation, training, latest versions, license
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57 and contact details.
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59 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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60 including FreeRTOS+Trace - an indispensable productivity tool.
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62 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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63 the code with commercial support, indemnification, and middleware, under
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64 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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65 provide a safety engineered and independently SIL3 certified version under
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66 the SafeRTOS brand: http://www.SafeRTOS.com.
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70 * This demo application creates six co-routines and two tasks (three including
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71 * the idle task). The co-routines execute as part of the idle task hook.
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73 * Five of the created co-routines are the standard 'co-routine flash'
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74 * co-routines contained within the Demo/Common/Minimal/crflash.c file and
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75 * documented on the FreeRTOS.org WEB site.
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77 * The 'LCD Task' rotates a string on the LCD, delaying between each character
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78 * as necessitated by the slow interface, and delaying between each string just
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79 * long enough to enable the text to be read.
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81 * The sixth co-routine and final task control the transmission and reception
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82 * of a string to UART 0. The co-routine periodically sends the first
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83 * character of the string to the UART, with the UART's TxEnd interrupt being
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84 * used to transmit the remaining characters. The UART's RxEnd interrupt
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85 * receives the characters and places them on a queue to be processed by the
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86 * 'COMs Rx' task. An error is latched should an unexpected character be
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87 * received, or any character be received out of sequence.
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89 * A loopback connector is required to ensure that each character transmitted
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90 * on the UART is also received on the same UART. For test purposes the UART
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91 * FIFO's are not utalised in order to maximise the interrupt overhead. Also
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92 * a pseudo random interval is used between the start of each transmission in
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93 * order that the resultant interrupts are more randomly distributed and
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94 * therefore more likely to highlight any problems.
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96 * The flash co-routines control LED's zero to four. LED five is toggled each
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97 * time the string is transmitted on the UART. LED six is toggled each time
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98 * the string is CORRECTLY received on the UART. LED seven is latched on should
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99 * an error be detected in any task or co-routine.
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101 * In addition the idle task makes repetative calls to
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102 * prvSetAndCheckRegisters(). This simply loads the general purpose registers
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103 * with a known value, then checks each register to ensure the held value is
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104 * still correct. As a low priority task this checking routine is likely to
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105 * get repeatedly swapped in and out. A register being found to contain an
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106 * incorrect value is therefore indicative of an error in the task switching
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111 /* Scheduler include files. */
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112 #include "FreeRTOS.h"
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115 #include "croutine.h"
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117 /* Demo application include files. */
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118 #include "partest.h"
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119 #include "crflash.h"
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121 /* Library include files. */
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122 #include "DriverLib.h"
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124 /* The time to delay between writing each character to the LCD. */
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125 #define mainCHAR_WRITE_DELAY ( 2 / portTICK_RATE_MS )
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127 /* The time to delay between writing each string to the LCD. */
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128 #define mainSTRING_WRITE_DELAY ( 400 / portTICK_RATE_MS )
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130 /* The number of flash co-routines to create. */
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131 #define mainNUM_FLASH_CO_ROUTINES ( 5 )
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133 /* The length of the queue used to pass received characters to the Comms Rx
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135 #define mainRX_QUEUE_LEN ( 5 )
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137 /* The priority of the co-routine used to initiate the transmission of the
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138 string on UART 0. */
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139 #define mainTX_CO_ROUTINE_PRIORITY ( 1 )
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141 /* Only one co-routine is created so its index is not important. */
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142 #define mainTX_CO_ROUTINE_INDEX ( 0 )
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144 /* The time between transmissions of the string on UART 0. This is pseudo
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145 random in order to generate a bit or randomness to when the interrupts occur.*/
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146 #define mainMIN_TX_DELAY ( 40 / portTICK_RATE_MS )
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147 #define mainMAX_TX_DELAY ( ( portTickType ) 0x7f )
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148 #define mainOFFSET_TIME ( ( portTickType ) 3 )
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150 /* The time the Comms Rx task should wait to receive a character. This should
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151 be slightly longer than the time between transmissions. If we do not receive
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152 a character after this time then there must be an error in the transmission or
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153 the timing of the transmission. */
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154 #define mainCOMMS_RX_DELAY ( mainMAX_TX_DELAY + 20 )
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156 /* The task priorites. */
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157 #define mainLCD_TASK_PRIORITY ( tskIDLE_PRIORITY )
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158 #define mainCOMMS_RX_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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160 /* The LED's toggled by the various tasks. */
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161 #define mainCOMMS_FAIL_LED ( 7 )
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162 #define mainCOMMS_RX_LED ( 6 )
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163 #define mainCOMMS_TX_LED ( 5 )
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165 /* The baud rate used by the UART comms tasks/co-routine. */
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166 #define mainBAUD_RATE ( 57600 )
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168 /* FIFO setting for the UART. The FIFO is not used to create a better test. */
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169 #define mainFIFO_SET ( 0x10 )
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171 /* The string that is transmitted on the UART contains sequentially the
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172 characters from mainFIRST_TX_CHAR to mainLAST_TX_CHAR. */
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173 #define mainFIRST_TX_CHAR '0'
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174 #define mainLAST_TX_CHAR 'z'
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176 /* Just used to walk through the program memory in order that some random data
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177 can be generated. */
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178 #define mainTOTAL_PROGRAM_MEMORY ( ( unsigned long * ) ( 8 * 1024 ) )
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179 #define mainFIRST_PROGRAM_BYTES ( ( unsigned long * ) 4 )
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181 /* The error routine that is called if the driver library encounters an error. */
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184 __error__(char *pcFilename, unsigned long ulLine)
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189 /*-----------------------------------------------------------*/
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192 * The task that rotates text on the LCD.
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194 static void vLCDTask( void * pvParameters );
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197 * The task that receives the characters from UART 0.
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199 static void vCommsRxTask( void * pvParameters );
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202 * The co-routine that periodically initiates the transmission of the string on
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205 static void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
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208 * Writes a string the the LCD.
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210 static void prvWriteString( const char *pcString );
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213 * Initialisation routine for the UART.
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215 static void vSerialInit( void );
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218 * Thread safe write to the PDC.
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220 static void prvPDCWrite( char cAddress, char cData );
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223 * Function to simply set a known value into the general purpose registers
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224 * then read them back to ensure they remain set correctly. An incorrect value
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225 * being indicative of an error in the task switching mechanism.
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227 void prvSetAndCheckRegisters( void );
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230 * Latch the LED that indicates that an error has occurred.
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232 void vSetErrorLED( void );
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235 * Sets up the PLL and ports used by the demo.
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237 static void prvSetupHardware( void );
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239 /*-----------------------------------------------------------*/
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241 /* Error flag set to pdFAIL if an error is encountered in the tasks/co-routines
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242 defined within this file. */
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243 unsigned portBASE_TYPE uxErrorStatus = pdPASS;
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245 /* The next character to transmit. */
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246 static char cNextChar;
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248 /* The queue used to transmit characters from the interrupt to the Comms Rx
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250 static xQueueHandle xCommsQueue;
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252 /*-----------------------------------------------------------*/
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256 /* Create the queue used to communicate between the UART ISR and the Comms
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258 xCommsQueue = xQueueCreate( mainRX_QUEUE_LEN, sizeof( char ) );
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260 /* Setup the ports used by the demo and the clock. */
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261 prvSetupHardware();
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263 /* Create the co-routines that flash the LED's. */
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264 vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );
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266 /* Create the co-routine that initiates the transmission of characters
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268 xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );
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270 /* Create the LCD and Comms Rx tasks. */
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271 xTaskCreate( vLCDTask, "LCD", configMINIMAL_STACK_SIZE, NULL, mainLCD_TASK_PRIORITY, NULL );
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272 xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );
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274 /* Start the scheduler running the tasks and co-routines just created. */
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275 vTaskStartScheduler();
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277 /* Should not get here unless we did not have enough memory to start the
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281 /*-----------------------------------------------------------*/
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283 static void prvSetupHardware( void )
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285 /* Setup the PLL. */
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286 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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288 /* Initialise the hardware used to talk to the LCD, LED's and UART. */
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290 vParTestInitialise();
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293 /*-----------------------------------------------------------*/
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295 void vApplicationIdleHook( void )
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297 /* The co-routines are executed in the idle task using the idle task
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301 /* Schedule the co-routines. */
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302 vCoRoutineSchedule();
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304 /* Run the register check function between each co-routine. */
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305 prvSetAndCheckRegisters();
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308 /*-----------------------------------------------------------*/
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310 static void prvWriteString( const char *pcString )
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312 /* Write pcString to the LED, pausing between each character. */
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313 prvPDCWrite(PDC_LCD_CSR, LCD_CLEAR);
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316 vTaskDelay( mainCHAR_WRITE_DELAY );
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317 prvPDCWrite( PDC_LCD_RAM, *pcString );
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321 /*-----------------------------------------------------------*/
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323 void vLCDTask( void * pvParameters )
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325 unsigned portBASE_TYPE uxIndex;
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326 const unsigned char ucCFGData[] = {
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327 0x30, /* Set data bus to 8-bits. */
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330 0x3C, /* Number of lines/font. */
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331 0x08, /* Display off. */
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332 0x01, /* Display clear. */
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333 0x06, /* Entry mode [cursor dir][shift]. */
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334 0x0C /* Display on [display on][curson on][blinking on]. */
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337 /* The strings that are written to the LCD. */
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338 const char *pcStringsToDisplay[] = {
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342 "www.FreeRTOS.org",
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346 /* Configure the LCD. */
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348 while( uxIndex < sizeof( ucCFGData ) )
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350 prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );
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352 vTaskDelay( mainCHAR_WRITE_DELAY );
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355 /* Turn the LCD Backlight on. */
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356 prvPDCWrite( PDC_CSR, 0x01 );
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358 /* Clear display. */
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359 vTaskDelay( mainCHAR_WRITE_DELAY );
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360 prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR );
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365 /* Display the string on the LCD. */
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366 prvWriteString( pcStringsToDisplay[ uxIndex ] );
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368 /* Move on to the next string - wrapping if necessary. */
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370 if( *( pcStringsToDisplay[ uxIndex ] ) == 0x00 )
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373 /* Longer pause on the last string to be sent. */
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374 vTaskDelay( mainSTRING_WRITE_DELAY * 2 );
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377 /* Wait until it is time to move onto the next string. */
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378 vTaskDelay( mainSTRING_WRITE_DELAY );
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381 /*-----------------------------------------------------------*/
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383 static void vCommsRxTask( void * pvParameters )
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385 static char cRxedChar, cExpectedChar;
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387 /* Set the char we expect to receive to the start of the string. */
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388 cExpectedChar = mainFIRST_TX_CHAR;
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392 /* Wait for a character to be received. */
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393 xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, mainCOMMS_RX_DELAY );
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395 /* Was the character recived (if any) the expected character. */
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396 if( cRxedChar != cExpectedChar )
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398 /* Got an unexpected character. This can sometimes occur when
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399 reseting the system using the debugger leaving characters already
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400 in the UART regsters. */
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401 uxErrorStatus = pdFAIL;
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403 /* Resync by waiting for the end of the current string. */
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404 while( cRxedChar != mainLAST_TX_CHAR )
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406 while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
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409 /* The next expected character is the start of the string again. */
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410 cExpectedChar = mainFIRST_TX_CHAR;
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414 if( cExpectedChar == mainLAST_TX_CHAR )
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416 /* We have reached the end of the string - we now expect to
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417 receive the first character in the string again. The LED is
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418 toggled to indicate that the entire string was received without
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420 vParTestToggleLED( mainCOMMS_RX_LED );
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421 cExpectedChar = mainFIRST_TX_CHAR;
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425 /* We got the expected character, we now expect to receive the
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426 next character in the string. */
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432 /*-----------------------------------------------------------*/
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434 static void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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436 portTickType xDelayPeriod;
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437 static unsigned long *pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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439 /* Co-routine MUST start with a call to crSTART. */
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440 crSTART( xHandle );
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444 /* Was the previously transmitted string received correctly? */
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445 if( uxErrorStatus != pdPASS )
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447 /* An error was encountered so set the error LED. */
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451 /* The next character to Tx is the first in the string. */
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452 cNextChar = mainFIRST_TX_CHAR;
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454 UARTIntDisable( UART0_BASE, UART_INT_TX );
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456 /* Send the first character. */
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457 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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459 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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462 /* Move the variable to the char to Tx on so the ISR transmits
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463 the next character in the string once this one has completed. */
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466 UARTIntEnable(UART0_BASE, UART_INT_TX);
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468 /* Toggle the LED to show a new string is being transmitted. */
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469 vParTestToggleLED( mainCOMMS_TX_LED );
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471 /* Delay before we start the string off again. A pseudo-random delay
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472 is used as this will provide a better test. */
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473 xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );
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476 if( pulRandomBytes > mainTOTAL_PROGRAM_MEMORY )
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478 pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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481 /* Make sure we don't wait too long... */
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482 xDelayPeriod &= mainMAX_TX_DELAY;
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484 /* ...but we do want to wait. */
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485 if( xDelayPeriod < mainMIN_TX_DELAY )
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487 xDelayPeriod = mainMIN_TX_DELAY;
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490 /* Block for the random(ish) time. */
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491 crDELAY( xHandle, xDelayPeriod );
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494 /* Co-routine MUST end with a call to crEND. */
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497 /*-----------------------------------------------------------*/
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499 static void vSerialInit( void )
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501 /* Enable the UART. GPIOA has already been initialised. */
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502 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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504 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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506 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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508 /* Configure the UART for 8-N-1 operation. */
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509 UARTConfigSet( UART0_BASE, mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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511 /* We dont want to use the fifo. This is for test purposes to generate
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512 as many interrupts as possible. */
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513 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
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515 /* Enable both Rx and Tx interrupts. */
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516 HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
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517 IntEnable( INT_UART0 );
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519 /*-----------------------------------------------------------*/
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521 void vUART_ISR(void)
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523 unsigned long ulStatus;
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525 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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527 /* What caused the interrupt. */
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528 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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530 /* Clear the interrupt. */
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531 UARTIntClear( UART0_BASE, ulStatus );
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533 /* Was an Rx interrpt pending? */
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534 if( ulStatus & UART_INT_RX )
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536 if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
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538 /* Get the char from the buffer and post it onto the queue of
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539 Rxed chars. Posting the character should wake the task that is
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540 blocked on the queue waiting for characters. */
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541 cRxedChar = ( char ) HWREG( UART0_BASE + UART_O_DR );
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542 xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
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546 /* Was a Tx interrupt pending? */
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547 if( ulStatus & UART_INT_TX )
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549 /* Send the next character in the string. We are not using the FIFO. */
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550 if( cNextChar <= mainLAST_TX_CHAR )
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552 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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554 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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560 /* If a task was woken by the character being received then we force
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561 a context switch to occur in case the task is of higher priority than
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562 the currently executing task (i.e. the task that this interrupt
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564 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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566 /*-----------------------------------------------------------*/
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568 static void prvPDCWrite( char cAddress, char cData )
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572 PDCWrite( cAddress, cData );
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576 /*-----------------------------------------------------------*/
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578 void vSetErrorLED( void )
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580 vParTestSetLED( mainCOMMS_FAIL_LED, pdTRUE );
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582 /*-----------------------------------------------------------*/
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584 void prvSetAndCheckRegisters( void )
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586 /* Fill the general purpose registers with known values. */
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587 __asm volatile( " mov r11, #10\n"
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588 " add r0, r11, #1\n"
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589 " add r1, r11, #2\n"
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590 " add r2, r11, #3\n"
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591 " add r3, r11, #4\n"
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592 " add r4, r11, #5\n"
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593 " add r5, r11, #6\n"
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594 " add r6, r11, #7\n"
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595 " add r7, r11, #8\n"
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596 " add r8, r11, #9\n"
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597 " add r9, r11, #10\n"
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598 " add r10, r11, #11\n"
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599 " add r12, r11, #12" );
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601 /* Check the values are as expected. */
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602 __asm volatile( " cmp r11, #10\n"
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603 " bne set_error_led\n"
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605 " bne set_error_led\n"
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607 " bne set_error_led\n"
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609 " bne set_error_led\n"
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611 " bne set_error_led\n"
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613 " bne set_error_led\n"
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615 " bne set_error_led\n"
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617 " bne set_error_led\n"
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619 " bne set_error_led\n"
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621 " bne set_error_led\n"
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623 " bne set_error_led\n"
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625 " bne set_error_led\n"
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627 " bne set_error_led\n"
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630 __asm volatile( "set_error_led:\n"
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632 " ldr r1, =vSetErrorLED\n"
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637 /*-----------------------------------------------------------*/
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projects / freertos / blob