2 FreeRTOS V6.0.0 - Copyright (C) 2009 Real Time Engineers Ltd.
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4 ***************************************************************************
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8 * + New to FreeRTOS, *
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9 * + Wanting to learn FreeRTOS or multitasking in general quickly *
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10 * + Looking for basic training, *
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11 * + Wanting to improve your FreeRTOS skills and productivity *
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13 * then take a look at the FreeRTOS eBook *
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15 * "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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16 * http://www.FreeRTOS.org/Documentation *
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18 * A pdf reference manual is also available. Both are usually delivered *
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19 * to your inbox within 20 minutes to two hours when purchased between 8am *
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20 * and 8pm GMT (although please allow up to 24 hours in case of *
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21 * exceptional circumstances). Thank you for your support! *
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23 ***************************************************************************
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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 exception to the GPL is included to allow you to distribute
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31 a combined work that includes FreeRTOS without being obliged to provide the
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32 source code for proprietary components outside of the FreeRTOS kernel.
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33 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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34 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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35 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 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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55 * This demo application creates six co-routines and two tasks (three including
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56 * the idle task). The co-routines execute as part of the idle task hook.
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58 * Five of the created co-routines are the standard 'co-routine flash'
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59 * co-routines contained within the Demo/Common/Minimal/crflash.c file and
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60 * documented on the FreeRTOS.org WEB site.
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62 * The 'LCD Task' rotates a string on the LCD, delaying between each character
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63 * as necessitated by the slow interface, and delaying between each string just
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64 * long enough to enable the text to be read.
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66 * The sixth co-routine and final task control the transmission and reception
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67 * of a string to UART 0. The co-routine periodically sends the first
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68 * character of the string to the UART, with the UART's TxEnd interrupt being
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69 * used to transmit the remaining characters. The UART's RxEnd interrupt
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70 * receives the characters and places them on a queue to be processed by the
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71 * 'COMs Rx' task. An error is latched should an unexpected character be
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72 * received, or any character be received out of sequence.
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74 * A loopback connector is required to ensure that each character transmitted
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75 * on the UART is also received on the same UART. For test purposes the UART
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76 * FIFO's are not utalised in order to maximise the interrupt overhead. Also
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77 * a pseudo random interval is used between the start of each transmission in
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78 * order that the resultant interrupts are more randomly distributed and
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79 * therefore more likely to highlight any problems.
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81 * The flash co-routines control LED's zero to four. LED five is toggled each
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82 * time the string is transmitted on the UART. LED six is toggled each time
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83 * the string is CORRECTLY received on the UART. LED seven is latched on should
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84 * an error be detected in any task or co-routine.
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86 * In addition the idle task makes repetative calls to
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87 * prvSetAndCheckRegisters(). This simply loads the general purpose registers
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88 * with a known value, then checks each register to ensure the held value is
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89 * still correct. As a low priority task this checking routine is likely to
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90 * get repeatedly swapped in and out. A register being found to contain an
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91 * incorrect value is therefore indicative of an error in the task switching
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96 /* Scheduler include files. */
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97 #include "FreeRTOS.h"
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100 #include "croutine.h"
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102 /* Demo application include files. */
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103 #include "partest.h"
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104 #include "crflash.h"
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106 /* Library include files. */
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107 #include "LM3Sxxx.h"
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110 /* The time to delay between writing each character to the LCD. */
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111 #define mainCHAR_WRITE_DELAY ( 2 / portTICK_RATE_MS )
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113 /* The time to delay between writing each string to the LCD. */
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114 #define mainSTRING_WRITE_DELAY ( 400 / portTICK_RATE_MS )
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116 /* The number of flash co-routines to create. */
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117 #define mainNUM_FLASH_CO_ROUTINES ( 5 )
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119 /* The length of the queue used to pass received characters to the Comms Rx
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121 #define mainRX_QUEUE_LEN ( 5 )
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123 /* The priority of the co-routine used to initiate the transmission of the
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124 string on UART 0. */
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125 #define mainTX_CO_ROUTINE_PRIORITY ( 1 )
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127 /* Only one co-routine is created so its index is not important. */
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128 #define mainTX_CO_ROUTINE_INDEX ( 0 )
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130 /* The time between transmissions of the string on UART 0. This is pseudo
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131 random in order to generate a bit or randomness to when the interrupts occur.*/
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132 #define mainMIN_TX_DELAY ( 40 / portTICK_RATE_MS )
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133 #define mainMAX_TX_DELAY ( ( portTickType ) 0x7f )
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134 #define mainOFFSET_TIME ( ( portTickType ) 3 )
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136 /* The time the Comms Rx task should wait to receive a character. This should
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137 be slightly longer than the time between transmissions. If we do not receive
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138 a character after this time then there must be an error in the transmission or
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139 the timing of the transmission. */
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140 #define mainCOMMS_RX_DELAY ( mainMAX_TX_DELAY + 20 )
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142 /* The task priorites. */
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143 #define mainLCD_TASK_PRIORITY ( tskIDLE_PRIORITY )
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144 #define mainCOMMS_RX_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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146 /* The LED's toggled by the various tasks. */
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147 #define mainCOMMS_FAIL_LED ( 7 )
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148 #define mainCOMMS_RX_LED ( 6 )
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149 #define mainCOMMS_TX_LED ( 5 )
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151 /* The baud rate used by the UART comms tasks/co-routine. */
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152 #define mainBAUD_RATE ( 57600 )
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154 /* FIFO setting for the UART. The FIFO is not used to create a better test. */
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155 #define mainFIFO_SET ( 0x10 )
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157 /* The string that is transmitted on the UART contains sequentially the
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158 characters from mainFIRST_TX_CHAR to mainLAST_TX_CHAR. */
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159 #define mainFIRST_TX_CHAR '0'
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160 #define mainLAST_TX_CHAR 'z'
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162 /* Just used to walk through the program memory in order that some random data
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163 can be generated. */
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164 #define mainTOTAL_PROGRAM_MEMORY ( ( unsigned long * ) ( 8 * 1024 ) )
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165 #define mainFIRST_PROGRAM_BYTES ( ( unsigned long * ) 4 )
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167 /*-----------------------------------------------------------*/
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170 * The task that rotates text on the LCD.
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172 static void vLCDTask( void * pvParameters );
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175 * The task that receives the characters from UART 0.
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177 static void vCommsRxTask( void * pvParameters );
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180 * The co-routine that periodically initiates the transmission of the string on
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183 static void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
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186 * Writes a string the the LCD.
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188 static void prvWriteString( const char *pcString );
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191 * Initialisation routine for the UART.
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193 static void vSerialInit( void );
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196 * Thread safe write to the PDC.
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198 static void prvPDCWrite( char cAddress, char cData );
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201 * Function to simply set a known value into the general purpose registers
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202 * then read them back to ensure they remain set correctly. An incorrect value
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203 * being indicative of an error in the task switching mechanism.
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205 void prvSetAndCheckRegisters( void );
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208 * Latch the LED that indicates that an error has occurred.
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210 void vSetErrorLED( void );
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213 * Sets up the PLL and ports used by the demo.
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215 static void prvSetupHardware( void );
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217 /*-----------------------------------------------------------*/
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219 /* Error flag set to pdFAIL if an error is encountered in the tasks/co-routines
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220 defined within this file. */
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221 unsigned portBASE_TYPE uxErrorStatus = pdPASS;
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223 /* The next character to transmit. */
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224 static char cNextChar;
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226 /* The queue used to transmit characters from the interrupt to the Comms Rx
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228 static xQueueHandle xCommsQueue;
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230 /*-----------------------------------------------------------*/
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234 /* Create the queue used to communicate between the UART ISR and the Comms
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236 xCommsQueue = xQueueCreate( mainRX_QUEUE_LEN, sizeof( char ) );
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238 /* Setup the ports used by the demo and the clock. */
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239 prvSetupHardware();
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241 /* Create the co-routines that flash the LED's. */
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242 vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );
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244 /* Create the co-routine that initiates the transmission of characters
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246 xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );
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248 /* Create the LCD and Comms Rx tasks. */
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249 xTaskCreate( vLCDTask, "LCD", configMINIMAL_STACK_SIZE, NULL, mainLCD_TASK_PRIORITY, NULL );
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250 xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );
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252 /* Start the scheduler running the tasks and co-routines just created. */
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253 vTaskStartScheduler();
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255 /* Should not get here unless we did not have enough memory to start the
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259 /*-----------------------------------------------------------*/
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261 static void prvSetupHardware( void )
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263 /* Setup the PLL. */
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264 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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266 /* Initialise the hardware used to talk to the LCD, LED's and UART. */
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268 vParTestInitialise();
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271 /*-----------------------------------------------------------*/
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273 void vApplicationIdleHook( void )
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275 /* The co-routines are executed in the idle task using the idle task
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279 /* Schedule the co-routines. */
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280 vCoRoutineSchedule();
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282 /* Run the register check function between each co-routine. */
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283 prvSetAndCheckRegisters();
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286 /*-----------------------------------------------------------*/
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288 static void prvWriteString( const char *pcString )
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290 /* Write pcString to the LED, pausing between each character. */
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291 prvPDCWrite(PDC_LCD_CSR, LCD_CLEAR);
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294 vTaskDelay( mainCHAR_WRITE_DELAY );
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295 prvPDCWrite( PDC_LCD_RAM, *pcString );
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299 /*-----------------------------------------------------------*/
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301 void vLCDTask( void * pvParameters )
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303 unsigned portBASE_TYPE uxIndex;
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304 const unsigned char ucCFGData[] = {
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305 0x30, /* Set data bus to 8-bits. */
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308 0x3C, /* Number of lines/font. */
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309 0x08, /* Display off. */
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310 0x01, /* Display clear. */
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311 0x06, /* Entry mode [cursor dir][shift]. */
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312 0x0C /* Display on [display on][curson on][blinking on]. */
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315 /* The strings that are written to the LCD. */
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316 const char *pcStringsToDisplay[] = {
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320 "www.FreeRTOS.org",
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324 /* Configure the LCD. */
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326 while( uxIndex < sizeof( ucCFGData ) )
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328 prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );
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330 vTaskDelay( mainCHAR_WRITE_DELAY );
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333 /* Turn the LCD Backlight on. */
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334 prvPDCWrite( PDC_CSR, 0x01 );
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336 /* Clear display. */
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337 vTaskDelay( mainCHAR_WRITE_DELAY );
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338 prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR );
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343 /* Display the string on the LCD. */
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344 prvWriteString( pcStringsToDisplay[ uxIndex ] );
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346 /* Move on to the next string - wrapping if necessary. */
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348 if( *( pcStringsToDisplay[ uxIndex ] ) == 0x00 )
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351 /* Longer pause on the last string to be sent. */
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352 vTaskDelay( mainSTRING_WRITE_DELAY * 2 );
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355 /* Wait until it is time to move onto the next string. */
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356 vTaskDelay( mainSTRING_WRITE_DELAY );
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359 /*-----------------------------------------------------------*/
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361 static void vCommsRxTask( void * pvParameters )
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363 static char cRxedChar, cExpectedChar;
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365 /* Set the char we expect to receive to the start of the string. */
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366 cExpectedChar = mainFIRST_TX_CHAR;
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370 /* Wait for a character to be received. */
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371 xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, mainCOMMS_RX_DELAY );
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373 /* Was the character recived (if any) the expected character. */
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374 if( cRxedChar != cExpectedChar )
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376 /* Got an unexpected character. This can sometimes occur when
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377 reseting the system using the debugger leaving characters already
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378 in the UART regsters. */
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379 uxErrorStatus = pdFAIL;
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381 /* Resync by waiting for the end of the current string. */
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382 while( cRxedChar != mainLAST_TX_CHAR )
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384 while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
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387 /* The next expected character is the start of the string again. */
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388 cExpectedChar = mainFIRST_TX_CHAR;
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392 if( cExpectedChar == mainLAST_TX_CHAR )
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394 /* We have reached the end of the string - we now expect to
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395 receive the first character in the string again. The LED is
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396 toggled to indicate that the entire string was received without
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398 vParTestToggleLED( mainCOMMS_RX_LED );
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399 cExpectedChar = mainFIRST_TX_CHAR;
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403 /* We got the expected character, we now expect to receive the
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404 next character in the string. */
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410 /*-----------------------------------------------------------*/
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412 static void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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414 portTickType xDelayPeriod;
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415 static unsigned long *pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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417 /* Co-routine MUST start with a call to crSTART. */
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418 crSTART( xHandle );
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422 /* Was the previously transmitted string received correctly? */
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423 if( uxErrorStatus != pdPASS )
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425 /* An error was encountered so set the error LED. */
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429 /* The next character to Tx is the first in the string. */
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430 cNextChar = mainFIRST_TX_CHAR;
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432 UARTIntDisable( UART0_BASE, UART_INT_TX );
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434 /* Send the first character. */
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435 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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437 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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440 /* Move the variable to the char to Tx on so the ISR transmits
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441 the next character in the string once this one has completed. */
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444 UARTIntEnable(UART0_BASE, UART_INT_TX);
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446 /* Toggle the LED to show a new string is being transmitted. */
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447 vParTestToggleLED( mainCOMMS_TX_LED );
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449 /* Delay before we start the string off again. A pseudo-random delay
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450 is used as this will provide a better test. */
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451 xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );
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454 if( pulRandomBytes > mainTOTAL_PROGRAM_MEMORY )
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456 pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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459 /* Make sure we don't wait too long... */
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460 xDelayPeriod &= mainMAX_TX_DELAY;
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462 /* ...but we do want to wait. */
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463 if( xDelayPeriod < mainMIN_TX_DELAY )
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465 xDelayPeriod = mainMIN_TX_DELAY;
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468 /* Block for the random(ish) time. */
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469 crDELAY( xHandle, xDelayPeriod );
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472 /* Co-routine MUST end with a call to crEND. */
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475 /*-----------------------------------------------------------*/
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477 static void vSerialInit( void )
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479 /* Enable the UART. GPIOA has already been initialised. */
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480 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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482 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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484 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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486 /* Configure the UART for 8-N-1 operation. */
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487 UARTConfigSet( UART0_BASE, mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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489 /* We dont want to use the fifo. This is for test purposes to generate
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490 as many interrupts as possible. */
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491 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
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493 /* Enable both Rx and Tx interrupts. */
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494 HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
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495 IntEnable( INT_UART0 );
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497 /*-----------------------------------------------------------*/
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499 void vUART_ISR(void)
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501 unsigned long ulStatus;
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503 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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505 /* What caused the interrupt. */
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506 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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508 /* Clear the interrupt. */
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509 UARTIntClear( UART0_BASE, ulStatus );
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511 /* Was an Rx interrpt pending? */
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512 if( ulStatus & UART_INT_RX )
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514 if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
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516 /* Get the char from the buffer and post it onto the queue of
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517 Rxed chars. Posting the character should wake the task that is
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518 blocked on the queue waiting for characters. */
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519 cRxedChar = ( char ) HWREG( UART0_BASE + UART_O_DR );
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520 xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
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524 /* Was a Tx interrupt pending? */
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525 if( ulStatus & UART_INT_TX )
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527 /* Send the next character in the string. We are not using the FIFO. */
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528 if( cNextChar <= mainLAST_TX_CHAR )
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530 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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532 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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538 /* If a task was woken by the character being received then we force
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539 a context switch to occur in case the task is of higher priority than
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540 the currently executing task (i.e. the task that this interrupt
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542 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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544 /*-----------------------------------------------------------*/
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546 static void prvPDCWrite( char cAddress, char cData )
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550 PDCWrite( cAddress, cData );
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554 /*-----------------------------------------------------------*/
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556 void vSetErrorLED( void )
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558 vParTestSetLED( mainCOMMS_FAIL_LED, pdTRUE );
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560 /*-----------------------------------------------------------*/
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562 __asm void prvSetAndCheckRegisters( void )
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564 extern vSetErrorLED
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566 /* Fill the general purpose registers with known values. */
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581 /* Check the values are as expected. */
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612 ldr r1, =vSetErrorLED
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617 /*-----------------------------------------------------------*/
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projects / freertos / blob