2 FreeRTOS.org V5.2.0 - 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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10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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15 You should have received a copy of the GNU General Public License along
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16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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19 A special exception to the GPL is included to allow you to distribute a
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20 combined work that includes FreeRTOS.org without being obliged to provide
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21 the source code for any proprietary components. See the licensing section
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22 of http://www.FreeRTOS.org for full details.
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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 six co-routines and two tasks (three including
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54 * the idle task). The co-routines execute as part of the idle task hook.
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56 * Five of the created co-routines are the standard 'co-routine flash'
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57 * co-routines contained within the Demo/Common/Minimal/crflash.c file and
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58 * documented on the FreeRTOS.org WEB site.
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60 * The 'LCD Task' rotates a string on the LCD, delaying between each character
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61 * as necessitated by the slow interface, and delaying between each string just
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62 * long enough to enable the text to be read.
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64 * The sixth co-routine and final task control the transmission and reception
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65 * of a string to UART 0. The co-routine periodically sends the first
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66 * character of the string to the UART, with the UART's TxEnd interrupt being
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67 * used to transmit the remaining characters. The UART's RxEnd interrupt
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68 * receives the characters and places them on a queue to be processed by the
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69 * 'COMs Rx' task. An error is latched should an unexpected character be
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70 * received, or any character be received out of sequence.
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72 * A loopback connector is required to ensure that each character transmitted
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73 * on the UART is also received on the same UART. For test purposes the UART
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74 * FIFO's are not utalised in order to maximise the interrupt overhead. Also
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75 * a pseudo random interval is used between the start of each transmission in
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76 * order that the resultant interrupts are more randomly distributed and
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77 * therefore more likely to highlight any problems.
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79 * The flash co-routines control LED's zero to four. LED five is toggled each
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80 * time the string is transmitted on the UART. LED six is toggled each time
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81 * the string is CORRECTLY received on the UART. LED seven is latched on should
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82 * an error be detected in any task or co-routine.
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84 * In addition the idle task makes repetative calls to
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85 * prvSetAndCheckRegisters(). This simply loads the general purpose registers
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86 * with a known value, then checks each register to ensure the held value is
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87 * still correct. As a low priority task this checking routine is likely to
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88 * get repeatedly swapped in and out. A register being found to contain an
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89 * incorrect value is therefore indicative of an error in the task switching
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94 /* Scheduler include files. */
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95 #include "FreeRTOS.h"
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98 #include "croutine.h"
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100 /* Demo application include files. */
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101 #include "partest.h"
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102 #include "crflash.h"
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104 /* Library include files. */
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105 #include "LM3Sxxx.h"
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108 /* The time to delay between writing each character to the LCD. */
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109 #define mainCHAR_WRITE_DELAY ( 2 / portTICK_RATE_MS )
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111 /* The time to delay between writing each string to the LCD. */
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112 #define mainSTRING_WRITE_DELAY ( 400 / portTICK_RATE_MS )
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114 /* The number of flash co-routines to create. */
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115 #define mainNUM_FLASH_CO_ROUTINES ( 5 )
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117 /* The length of the queue used to pass received characters to the Comms Rx
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119 #define mainRX_QUEUE_LEN ( 5 )
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121 /* The priority of the co-routine used to initiate the transmission of the
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122 string on UART 0. */
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123 #define mainTX_CO_ROUTINE_PRIORITY ( 1 )
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125 /* Only one co-routine is created so its index is not important. */
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126 #define mainTX_CO_ROUTINE_INDEX ( 0 )
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128 /* The time between transmissions of the string on UART 0. This is pseudo
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129 random in order to generate a bit or randomness to when the interrupts occur.*/
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130 #define mainMIN_TX_DELAY ( 40 / portTICK_RATE_MS )
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131 #define mainMAX_TX_DELAY ( ( portTickType ) 0x7f )
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132 #define mainOFFSET_TIME ( ( portTickType ) 3 )
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134 /* The time the Comms Rx task should wait to receive a character. This should
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135 be slightly longer than the time between transmissions. If we do not receive
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136 a character after this time then there must be an error in the transmission or
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137 the timing of the transmission. */
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138 #define mainCOMMS_RX_DELAY ( mainMAX_TX_DELAY + 20 )
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140 /* The task priorites. */
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141 #define mainLCD_TASK_PRIORITY ( tskIDLE_PRIORITY )
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142 #define mainCOMMS_RX_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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144 /* The LED's toggled by the various tasks. */
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145 #define mainCOMMS_FAIL_LED ( 7 )
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146 #define mainCOMMS_RX_LED ( 6 )
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147 #define mainCOMMS_TX_LED ( 5 )
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149 /* The baud rate used by the UART comms tasks/co-routine. */
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150 #define mainBAUD_RATE ( 57600 )
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152 /* FIFO setting for the UART. The FIFO is not used to create a better test. */
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153 #define mainFIFO_SET ( 0x10 )
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155 /* The string that is transmitted on the UART contains sequentially the
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156 characters from mainFIRST_TX_CHAR to mainLAST_TX_CHAR. */
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157 #define mainFIRST_TX_CHAR '0'
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158 #define mainLAST_TX_CHAR 'z'
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160 /* Just used to walk through the program memory in order that some random data
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161 can be generated. */
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162 #define mainTOTAL_PROGRAM_MEMORY ( ( unsigned portLONG * ) ( 8 * 1024 ) )
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163 #define mainFIRST_PROGRAM_BYTES ( ( unsigned portLONG * ) 4 )
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165 /*-----------------------------------------------------------*/
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168 * The task that rotates text on the LCD.
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170 static void vLCDTask( void * pvParameters );
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173 * The task that receives the characters from UART 0.
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175 static void vCommsRxTask( void * pvParameters );
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178 * The co-routine that periodically initiates the transmission of the string on
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181 static void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex );
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184 * Writes a string the the LCD.
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186 static void prvWriteString( const portCHAR *pcString );
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189 * Initialisation routine for the UART.
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191 static void vSerialInit( void );
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194 * Thread safe write to the PDC.
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196 static void prvPDCWrite( portCHAR cAddress, portCHAR cData );
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199 * Function to simply set a known value into the general purpose registers
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200 * then read them back to ensure they remain set correctly. An incorrect value
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201 * being indicative of an error in the task switching mechanism.
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203 void prvSetAndCheckRegisters( void );
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206 * Latch the LED that indicates that an error has occurred.
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208 void vSetErrorLED( void );
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211 * Sets up the PLL and ports used by the demo.
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213 static void prvSetupHardware( void );
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215 /*-----------------------------------------------------------*/
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217 /* Error flag set to pdFAIL if an error is encountered in the tasks/co-routines
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218 defined within this file. */
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219 unsigned portBASE_TYPE uxErrorStatus = pdPASS;
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221 /* The next character to transmit. */
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222 static portCHAR cNextChar;
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224 /* The queue used to transmit characters from the interrupt to the Comms Rx
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226 static xQueueHandle xCommsQueue;
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228 /*-----------------------------------------------------------*/
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232 /* Create the queue used to communicate between the UART ISR and the Comms
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234 xCommsQueue = xQueueCreate( mainRX_QUEUE_LEN, sizeof( portCHAR ) );
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236 /* Setup the ports used by the demo and the clock. */
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237 prvSetupHardware();
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239 /* Create the co-routines that flash the LED's. */
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240 vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );
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242 /* Create the co-routine that initiates the transmission of characters
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244 xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );
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246 /* Create the LCD and Comms Rx tasks. */
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247 xTaskCreate( vLCDTask, "LCD", configMINIMAL_STACK_SIZE, NULL, mainLCD_TASK_PRIORITY, NULL );
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248 xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );
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250 /* Start the scheduler running the tasks and co-routines just created. */
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251 vTaskStartScheduler();
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253 /* Should not get here unless we did not have enough memory to start the
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257 /*-----------------------------------------------------------*/
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259 static void prvSetupHardware( void )
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261 /* Setup the PLL. */
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262 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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264 /* Initialise the hardware used to talk to the LCD, LED's and UART. */
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266 vParTestInitialise();
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269 /*-----------------------------------------------------------*/
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271 void vApplicationIdleHook( void )
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273 /* The co-routines are executed in the idle task using the idle task
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277 /* Schedule the co-routines. */
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278 vCoRoutineSchedule();
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280 /* Run the register check function between each co-routine. */
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281 prvSetAndCheckRegisters();
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284 /*-----------------------------------------------------------*/
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286 static void prvWriteString( const portCHAR *pcString )
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288 /* Write pcString to the LED, pausing between each character. */
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289 prvPDCWrite(PDC_LCD_CSR, LCD_CLEAR);
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292 vTaskDelay( mainCHAR_WRITE_DELAY );
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293 prvPDCWrite( PDC_LCD_RAM, *pcString );
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297 /*-----------------------------------------------------------*/
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299 void vLCDTask( void * pvParameters )
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301 unsigned portBASE_TYPE uxIndex;
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302 const unsigned portCHAR ucCFGData[] = {
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303 0x30, /* Set data bus to 8-bits. */
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306 0x3C, /* Number of lines/font. */
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307 0x08, /* Display off. */
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308 0x01, /* Display clear. */
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309 0x06, /* Entry mode [cursor dir][shift]. */
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310 0x0C /* Display on [display on][curson on][blinking on]. */
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313 /* The strings that are written to the LCD. */
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314 const portCHAR *pcStringsToDisplay[] = {
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318 "www.FreeRTOS.org",
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322 /* Configure the LCD. */
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324 while( uxIndex < sizeof( ucCFGData ) )
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326 prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );
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328 vTaskDelay( mainCHAR_WRITE_DELAY );
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331 /* Turn the LCD Backlight on. */
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332 prvPDCWrite( PDC_CSR, 0x01 );
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334 /* Clear display. */
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335 vTaskDelay( mainCHAR_WRITE_DELAY );
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336 prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR );
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341 /* Display the string on the LCD. */
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342 prvWriteString( pcStringsToDisplay[ uxIndex ] );
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344 /* Move on to the next string - wrapping if necessary. */
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346 if( *( pcStringsToDisplay[ uxIndex ] ) == 0x00 )
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349 /* Longer pause on the last string to be sent. */
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350 vTaskDelay( mainSTRING_WRITE_DELAY * 2 );
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353 /* Wait until it is time to move onto the next string. */
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354 vTaskDelay( mainSTRING_WRITE_DELAY );
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357 /*-----------------------------------------------------------*/
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359 static void vCommsRxTask( void * pvParameters )
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361 static portCHAR cRxedChar, cExpectedChar;
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363 /* Set the char we expect to receive to the start of the string. */
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364 cExpectedChar = mainFIRST_TX_CHAR;
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368 /* Wait for a character to be received. */
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369 xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, mainCOMMS_RX_DELAY );
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371 /* Was the character recived (if any) the expected character. */
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372 if( cRxedChar != cExpectedChar )
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374 /* Got an unexpected character. This can sometimes occur when
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375 reseting the system using the debugger leaving characters already
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376 in the UART regsters. */
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377 uxErrorStatus = pdFAIL;
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379 /* Resync by waiting for the end of the current string. */
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380 while( cRxedChar != mainLAST_TX_CHAR )
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382 while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
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385 /* The next expected character is the start of the string again. */
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386 cExpectedChar = mainFIRST_TX_CHAR;
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390 if( cExpectedChar == mainLAST_TX_CHAR )
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392 /* We have reached the end of the string - we now expect to
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393 receive the first character in the string again. The LED is
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394 toggled to indicate that the entire string was received without
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396 vParTestToggleLED( mainCOMMS_RX_LED );
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397 cExpectedChar = mainFIRST_TX_CHAR;
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401 /* We got the expected character, we now expect to receive the
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402 next character in the string. */
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408 /*-----------------------------------------------------------*/
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410 static void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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412 portTickType xDelayPeriod;
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413 static unsigned portLONG *pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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415 /* Co-routine MUST start with a call to crSTART. */
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416 crSTART( xHandle );
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420 /* Was the previously transmitted string received correctly? */
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421 if( uxErrorStatus != pdPASS )
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423 /* An error was encountered so set the error LED. */
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427 /* The next character to Tx is the first in the string. */
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428 cNextChar = mainFIRST_TX_CHAR;
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430 UARTIntDisable( UART0_BASE, UART_INT_TX );
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432 /* Send the first character. */
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433 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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435 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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438 /* Move the variable to the char to Tx on so the ISR transmits
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439 the next character in the string once this one has completed. */
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442 UARTIntEnable(UART0_BASE, UART_INT_TX);
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444 /* Toggle the LED to show a new string is being transmitted. */
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445 vParTestToggleLED( mainCOMMS_TX_LED );
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447 /* Delay before we start the string off again. A pseudo-random delay
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448 is used as this will provide a better test. */
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449 xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );
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452 if( pulRandomBytes > mainTOTAL_PROGRAM_MEMORY )
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454 pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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457 /* Make sure we don't wait too long... */
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458 xDelayPeriod &= mainMAX_TX_DELAY;
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460 /* ...but we do want to wait. */
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461 if( xDelayPeriod < mainMIN_TX_DELAY )
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463 xDelayPeriod = mainMIN_TX_DELAY;
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466 /* Block for the random(ish) time. */
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467 crDELAY( xHandle, xDelayPeriod );
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470 /* Co-routine MUST end with a call to crEND. */
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473 /*-----------------------------------------------------------*/
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475 static void vSerialInit( void )
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477 /* Enable the UART. GPIOA has already been initialised. */
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478 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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480 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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482 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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484 /* Configure the UART for 8-N-1 operation. */
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485 UARTConfigSet( UART0_BASE, mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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487 /* We dont want to use the fifo. This is for test purposes to generate
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488 as many interrupts as possible. */
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489 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
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491 /* Enable both Rx and Tx interrupts. */
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492 HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
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493 IntEnable( INT_UART0 );
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495 /*-----------------------------------------------------------*/
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497 void vUART_ISR(void)
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499 unsigned portLONG ulStatus;
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500 portCHAR cRxedChar;
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501 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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503 /* What caused the interrupt. */
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504 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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506 /* Clear the interrupt. */
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507 UARTIntClear( UART0_BASE, ulStatus );
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509 /* Was an Rx interrpt pending? */
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510 if( ulStatus & UART_INT_RX )
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512 if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
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514 /* Get the char from the buffer and post it onto the queue of
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515 Rxed chars. Posting the character should wake the task that is
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516 blocked on the queue waiting for characters. */
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517 cRxedChar = ( portCHAR ) HWREG( UART0_BASE + UART_O_DR );
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518 xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
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522 /* Was a Tx interrupt pending? */
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523 if( ulStatus & UART_INT_TX )
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525 /* Send the next character in the string. We are not using the FIFO. */
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526 if( cNextChar <= mainLAST_TX_CHAR )
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528 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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530 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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536 /* If a task was woken by the character being received then we force
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537 a context switch to occur in case the task is of higher priority than
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538 the currently executing task (i.e. the task that this interrupt
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540 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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542 /*-----------------------------------------------------------*/
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544 static void prvPDCWrite( portCHAR cAddress, portCHAR cData )
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548 PDCWrite( cAddress, cData );
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552 /*-----------------------------------------------------------*/
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554 void vSetErrorLED( void )
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556 vParTestSetLED( mainCOMMS_FAIL_LED, pdTRUE );
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558 /*-----------------------------------------------------------*/
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560 __asm void prvSetAndCheckRegisters( void )
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562 extern vSetErrorLED
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564 /* Fill the general purpose registers with known values. */
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579 /* Check the values are as expected. */
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610 ldr r1, =vSetErrorLED
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615 /*-----------------------------------------------------------*/
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