2 FreeRTOS.org V5.3.1 - Copyright (C) 2003-2009 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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9 **NOTE** The exception to the GPL is included to allow you to distribute a
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10 combined work that includes FreeRTOS.org without being obliged to provide
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11 the source code for any proprietary components. Alternative commercial
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12 license and support terms are also available upon request. See the
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13 licensing section of http://www.FreeRTOS.org for full details.
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15 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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16 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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20 You should have received a copy of the GNU General Public License along
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21 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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22 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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53 * This demo application creates eight co-routines and four tasks (five
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54 * including the idle task). The co-routines execute as part of the idle task
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55 * hook. The application is limited in size to allow its compilation using
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56 * the KickStart version of the IAR compiler.
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58 * Six 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' waits on a message queue for messages informing it what and
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63 * where to display text. This is the only task that accesses the LCD
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64 * so mutual exclusion is guaranteed.
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66 * The 'LCD Message Task' periodically sends strings to the LCD Task using
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67 * the message queue. The strings are rotated to form a short message and
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68 * are written to the top row of the LCD.
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70 * The 'ADC Co-routine' periodically reads the ADC input that is connected to
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71 * the light sensor, forms a short message from the value, and then sends this
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72 * message to the LCD Task using the same message queue. The ADC readings are
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73 * displayed on the bottom row of the LCD.
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75 * The eighth co-routine and final task control the transmission and reception
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76 * of a string to UART 0. The co-routine periodically sends the first
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77 * character of the string to the UART, with the UART's TxEnd interrupt being
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78 * used to transmit the remaining characters. The UART's RxEnd interrupt
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79 * receives the characters and places them on a queue to be processed by the
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80 * 'COMs Rx' task. An error is latched should an unexpected character be
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81 * received, or any character be received out of sequence.
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83 * A loopback connector is required to ensure that each character transmitted
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84 * on the UART is also received on the same UART. For test purposes the UART
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85 * FIFO's are not utalised in order to maximise the interrupt overhead. Also
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86 * a pseudo random interval is used between the start of each transmission in
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87 * order that the resultant interrupts are more randomly distributed and
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88 * therefore more likely to highlight any problems.
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90 * The flash co-routines control LED's zero to four. LED five is toggled each
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91 * time the string is transmitted on the UART. LED six is toggled each time
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92 * the string is CORRECTLY received on the UART. LED seven is latched on
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93 * should an error be detected in any task or co-routine.
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95 * In addition the idle task makes repetitive calls to
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96 * vSetAndCheckRegisters(). This simply loads the general purpose registers
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97 * with a known value, then checks each register to ensure the held value is
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98 * still correct. As a low priority task this checking routine is likely to
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99 * get repeatedly swapped in and out. A register being found to contain an
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100 * incorrect value is therefore indicative of an error in the task switching
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105 /* standard include files. */
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108 /* Scheduler include files. */
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109 #include "FreeRTOS.h"
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112 #include "croutine.h"
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114 /* Demo application include files. */
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115 #include "partest.h"
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116 #include "crflash.h"
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117 #include "commstest.h"
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119 /* Library include files. */
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120 #include "DriverLib.h"
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122 /* The time to delay between writing each character to the LCD. */
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123 #define mainCHAR_WRITE_DELAY ( 2 / portTICK_RATE_MS )
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125 /* The time to delay between writing each string to the LCD. */
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126 #define mainSTRING_WRITE_DELAY ( 400 / portTICK_RATE_MS )
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128 #define mainADC_DELAY ( 200 / 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 send messages to the LCD task. */
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134 #define mainLCD_QUEUE_LEN ( 3 )
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136 /* The priority of the co-routine used to initiate the transmission of the
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137 string on UART 0. */
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138 #define mainTX_CO_ROUTINE_PRIORITY ( 1 )
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139 #define mainADC_CO_ROUTINE_PRIORITY ( 2 )
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141 /* Only one of each 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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143 #define mainADC_CO_ROUTINE_INDEX ( 0 )
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145 /* The task priorities. */
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146 #define mainLCD_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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147 #define mainMSG_TASK_PRIORITY ( mainLCD_TASK_PRIORITY - 1 )
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148 #define mainCOMMS_RX_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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150 /* The LCD had two rows. */
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151 #define mainTOP_ROW 0
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152 #define mainBOTTOM_ROW 1
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154 /* Dimension for the buffer into which the ADC value string is written. */
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155 #define mainMAX_ADC_STRING_LEN 20
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157 /* The LED that is lit should an error be detected in any of the tasks or
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159 #define mainFAIL_LED ( 7 )
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161 /*-----------------------------------------------------------*/
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164 * The task that displays text on the LCD.
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166 static void prvLCDTask( void * pvParameters );
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169 * The task that sends messages to be displayed on the top row of the LCD.
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171 static void prvLCDMessageTask( void * pvParameters );
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174 * The co-routine that reads the ADC and sends messages for display on the
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175 * bottom row of the LCD.
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177 static void prvADCCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
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180 * Function to simply set a known value into the general purpose registers
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181 * then read them back to ensure they remain set correctly. An incorrect value
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182 * being indicative of an error in the task switching mechanism.
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184 extern void vSetAndCheckRegisters( void );
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187 * Latch the LED that indicates that an error has occurred.
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189 void vSetErrorLED( void );
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192 * Thread safe write to the PDC.
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194 static void prvPDCWrite( portCHAR cAddress, portCHAR cData );
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197 * Sets up the hardware used by the demo.
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199 static void prvSetupHardware( void );
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202 /*-----------------------------------------------------------*/
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204 /* The structure that is passed on the LCD message queue. */
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207 portCHAR **ppcMessageToDisplay; /*<< Points to a char* pointing to the message to display. */
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208 portBASE_TYPE xRow; /*<< The row on which the message should be displayed. */
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211 /* Error flag set to pdFAIL if an error is encountered in the tasks/co-routines
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212 defined within this file. */
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213 unsigned portBASE_TYPE uxErrorStatus = pdPASS;
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215 /* The queue used to transmit messages to the LCD task. */
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216 static xQueueHandle xLCDQueue;
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218 /*-----------------------------------------------------------*/
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221 * Setup the hardware, create the tasks/co-routines, then start the scheduler.
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225 /* Create the queue used by tasks wanting to write to the LCD. */
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226 xLCDQueue = xQueueCreate( mainLCD_QUEUE_LEN, sizeof( xLCDMessage ) );
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228 /* Setup the ports used by the demo and the clock. */
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229 prvSetupHardware();
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231 /* Create the co-routines that flash the LED's. */
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232 vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );
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234 /* Create the co-routine that initiates the transmission of characters
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235 on the UART and the task that receives them, as described at the top of
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237 xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );
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238 xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );
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240 /* Create the task that waits for messages to display on the LCD, plus the
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241 task and co-routine that send messages for display (as described at the top
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243 xTaskCreate( prvLCDTask, "LCD", configMINIMAL_STACK_SIZE, ( void * ) &xLCDQueue, mainLCD_TASK_PRIORITY, NULL );
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244 xTaskCreate( prvLCDMessageTask, "MSG", configMINIMAL_STACK_SIZE, ( void * ) &xLCDQueue, mainMSG_TASK_PRIORITY, NULL );
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245 xCoRoutineCreate( prvADCCoRoutine, mainADC_CO_ROUTINE_PRIORITY, mainADC_CO_ROUTINE_INDEX );
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247 /* Start the scheduler running the tasks and co-routines just created. */
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248 vTaskStartScheduler();
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250 /* Should not get here unless we did not have enough memory to start the
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254 /*-----------------------------------------------------------*/
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256 static void prvLCDMessageTask( void * pvParameters )
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258 /* The strings that are written to the LCD. */
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259 portCHAR *pcStringsToDisplay[] = {
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263 "www.FreeRTOS.org",
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267 xQueueHandle *pxLCDQueue;
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268 xLCDMessage xMessageToSend;
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269 portBASE_TYPE xIndex = 0;
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271 /* To test the parameter passing mechanism, the queue on which messages are
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272 posted is passed in as a parameter even though it is available as a file
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273 scope variable anyway. */
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274 pxLCDQueue = ( xQueueHandle * ) pvParameters;
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278 /* Wait until it is time to move onto the next string. */
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279 vTaskDelay( mainSTRING_WRITE_DELAY );
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281 /* Create the message object to send to the LCD task. */
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282 xMessageToSend.ppcMessageToDisplay = &pcStringsToDisplay[ xIndex ];
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283 xMessageToSend.xRow = mainTOP_ROW;
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285 /* Post the message to be displayed. */
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286 if( !xQueueSend( *pxLCDQueue, ( void * ) &xMessageToSend, 0 ) )
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288 uxErrorStatus = pdFAIL;
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291 /* Move onto the next message, wrapping when necessary. */
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293 if( *( pcStringsToDisplay[ xIndex ] ) == 0x00 )
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297 /* Delay longer before going back to the start of the messages. */
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298 vTaskDelay( mainSTRING_WRITE_DELAY * 2 );
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302 /*-----------------------------------------------------------*/
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304 void prvLCDTask( void * pvParameters )
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306 unsigned portBASE_TYPE uxIndex;
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307 xQueueHandle *pxLCDQueue;
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308 xLCDMessage xReceivedMessage;
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309 portCHAR *pcString;
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310 const unsigned portCHAR ucCFGData[] = {
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311 0x30, /* Set data bus to 8-bits. */
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314 0x3C, /* Number of lines/font. */
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315 0x08, /* Display off. */
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316 0x01, /* Display clear. */
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317 0x06, /* Entry mode [cursor dir][shift]. */
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318 0x0C /* Display on [display on][curson on][blinking on]. */
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321 /* To test the parameter passing mechanism, the queue on which messages are
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322 received is passed in as a parameter even though it is available as a file
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323 scope variable anyway. */
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324 pxLCDQueue = ( xQueueHandle * ) pvParameters;
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326 /* Configure the LCD. */
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328 while( uxIndex < sizeof( ucCFGData ) )
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330 prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );
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332 vTaskDelay( mainCHAR_WRITE_DELAY );
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335 /* Turn the LCD Backlight on. */
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336 prvPDCWrite( PDC_CSR, 0x01 );
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338 /* Clear display. */
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339 vTaskDelay( mainCHAR_WRITE_DELAY );
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340 prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR );
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345 /* Wait for a message to arrive. */
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346 if( xQueueReceive( *pxLCDQueue, &xReceivedMessage, portMAX_DELAY ) )
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348 /* Which row does the received message say to write to? */
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349 PDCLCDSetPos( 0, xReceivedMessage.xRow );
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351 /* Where is the string we are going to display? */
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352 pcString = *xReceivedMessage.ppcMessageToDisplay;
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356 /* Don't write out the string too quickly as LCD's are usually
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357 pretty slow devices. */
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358 vTaskDelay( mainCHAR_WRITE_DELAY );
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359 prvPDCWrite( PDC_LCD_RAM, *pcString );
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365 /*-----------------------------------------------------------*/
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367 static void prvADCCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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369 static unsigned portLONG ulADCValue;
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370 static portCHAR cMessageBuffer[ mainMAX_ADC_STRING_LEN ];
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371 static portCHAR *pcMessage;
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372 static xLCDMessage xMessageToSend;
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374 /* Co-routines MUST start with a call to crSTART(). */
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375 crSTART( xHandle );
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379 /* Start an ADC conversion. */
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380 ADCProcessorTrigger( ADC_BASE, 0 );
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382 /* Simply delay - when we unblock the result should be available */
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383 crDELAY( xHandle, mainADC_DELAY );
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385 /* Get the ADC result. */
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386 ADCSequenceDataGet( ADC_BASE, 0, &ulADCValue );
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388 /* Create a string with the result. */
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389 sprintf( cMessageBuffer, "ADC = %d ", ulADCValue );
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390 pcMessage = cMessageBuffer;
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392 /* Configure the message we are going to send for display. */
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393 xMessageToSend.ppcMessageToDisplay = ( portCHAR** ) &pcMessage;
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394 xMessageToSend.xRow = mainBOTTOM_ROW;
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396 /* Send the string to the LCD task for display. We are sending
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397 on a task queue so do not have the option to block. */
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398 if( !xQueueSend( xLCDQueue, ( void * ) &xMessageToSend, 0 ) )
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400 uxErrorStatus = pdFAIL;
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404 /* Co-routines MUST end with a call to crEND(). */
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407 /*-----------------------------------------------------------*/
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409 static void prvSetupHardware( void )
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411 /* Setup the PLL. */
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412 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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414 /* Initialise the hardware used to talk to the LCD, LED's and UART. */
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416 vParTestInitialise();
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419 /* The ADC is used to read the light sensor. */
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420 SysCtlPeripheralEnable( SYSCTL_PERIPH_ADC );
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421 ADCSequenceConfigure( ADC_BASE, 3, ADC_TRIGGER_PROCESSOR, 0);
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422 ADCSequenceStepConfigure( ADC_BASE, 0, 0, ADC_CTL_CH0 | ADC_CTL_END );
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423 ADCSequenceEnable( ADC_BASE, 0 );
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426 /*-----------------------------------------------------------*/
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428 static void prvPDCWrite( portCHAR cAddress, portCHAR cData )
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432 PDCWrite( cAddress, cData );
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436 /*-----------------------------------------------------------*/
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438 void vSetErrorLED( void )
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440 vParTestSetLED( mainFAIL_LED, pdTRUE );
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442 /*-----------------------------------------------------------*/
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444 void vApplicationIdleHook( void )
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446 /* The co-routines are executed in the idle task using the idle task
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450 /* Schedule the co-routines. */
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451 vCoRoutineSchedule();
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453 /* Run the register check function between each co-routine. */
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454 vSetAndCheckRegisters();
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456 /* See if the comms task and co-routine has found any errors. */
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457 if( uxGetCommsStatus() != pdPASS )
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459 vParTestSetLED( mainFAIL_LED, pdTRUE );
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463 /*-----------------------------------------------------------*/
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