2 * FreeRTOS Kernel V10.2.1
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3 * Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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29 * This demo application creates six co-routines and two tasks (three including
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30 * the idle task). The co-routines execute as part of the idle task hook.
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32 * Five of the created co-routines are the standard 'co-routine flash'
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33 * co-routines contained within the Demo/Common/Minimal/crflash.c file and
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34 * documented on the FreeRTOS.org WEB site.
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36 * The 'LCD Task' rotates a string on the LCD, delaying between each character
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37 * as necessitated by the slow interface, and delaying between each string just
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38 * long enough to enable the text to be read.
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40 * The sixth co-routine and final task control the transmission and reception
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41 * of a string to UART 0. The co-routine periodically sends the first
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42 * character of the string to the UART, with the UART's TxEnd interrupt being
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43 * used to transmit the remaining characters. The UART's RxEnd interrupt
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44 * receives the characters and places them on a queue to be processed by the
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45 * 'COMs Rx' task. An error is latched should an unexpected character be
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46 * received, or any character be received out of sequence.
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48 * A loopback connector is required to ensure that each character transmitted
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49 * on the UART is also received on the same UART. For test purposes the UART
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50 * FIFO's are not utalised in order to maximise the interrupt overhead. Also
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51 * a pseudo random interval is used between the start of each transmission in
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52 * order that the resultant interrupts are more randomly distributed and
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53 * therefore more likely to highlight any problems.
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55 * The flash co-routines control LED's zero to four. LED five is toggled each
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56 * time the string is transmitted on the UART. LED six is toggled each time
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57 * the string is CORRECTLY received on the UART. LED seven is latched on should
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58 * an error be detected in any task or co-routine.
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60 * In addition the idle task makes repetative calls to
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61 * prvSetAndCheckRegisters(). This simply loads the general purpose registers
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62 * with a known value, then checks each register to ensure the held value is
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63 * still correct. As a low priority task this checking routine is likely to
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64 * get repeatedly swapped in and out. A register being found to contain an
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65 * incorrect value is therefore indicative of an error in the task switching
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70 /* Scheduler include files. */
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71 #include "FreeRTOS.h"
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74 #include "croutine.h"
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76 /* Demo application include files. */
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77 #include "partest.h"
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78 #include "crflash.h"
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80 /* Library include files. */
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81 #include "DriverLib.h"
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83 /* The time to delay between writing each character to the LCD. */
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84 #define mainCHAR_WRITE_DELAY ( 2 / portTICK_PERIOD_MS )
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86 /* The time to delay between writing each string to the LCD. */
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87 #define mainSTRING_WRITE_DELAY ( 400 / portTICK_PERIOD_MS )
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89 /* The number of flash co-routines to create. */
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90 #define mainNUM_FLASH_CO_ROUTINES ( 5 )
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92 /* The length of the queue used to pass received characters to the Comms Rx
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94 #define mainRX_QUEUE_LEN ( 5 )
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96 /* The priority of the co-routine used to initiate the transmission of the
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97 string on UART 0. */
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98 #define mainTX_CO_ROUTINE_PRIORITY ( 1 )
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100 /* Only one co-routine is created so its index is not important. */
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101 #define mainTX_CO_ROUTINE_INDEX ( 0 )
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103 /* The time between transmissions of the string on UART 0. This is pseudo
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104 random in order to generate a bit or randomness to when the interrupts occur.*/
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105 #define mainMIN_TX_DELAY ( 40 / portTICK_PERIOD_MS )
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106 #define mainMAX_TX_DELAY ( ( TickType_t ) 0x7f )
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107 #define mainOFFSET_TIME ( ( TickType_t ) 3 )
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109 /* The time the Comms Rx task should wait to receive a character. This should
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110 be slightly longer than the time between transmissions. If we do not receive
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111 a character after this time then there must be an error in the transmission or
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112 the timing of the transmission. */
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113 #define mainCOMMS_RX_DELAY ( mainMAX_TX_DELAY + 20 )
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115 /* The task priorites. */
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116 #define mainLCD_TASK_PRIORITY ( tskIDLE_PRIORITY )
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117 #define mainCOMMS_RX_TASK_PRIORITY ( tskIDLE_PRIORITY + 1 )
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119 /* The LED's toggled by the various tasks. */
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120 #define mainCOMMS_FAIL_LED ( 7 )
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121 #define mainCOMMS_RX_LED ( 6 )
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122 #define mainCOMMS_TX_LED ( 5 )
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124 /* The baud rate used by the UART comms tasks/co-routine. */
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125 #define mainBAUD_RATE ( 57600 )
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127 /* FIFO setting for the UART. The FIFO is not used to create a better test. */
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128 #define mainFIFO_SET ( 0x10 )
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130 /* The string that is transmitted on the UART contains sequentially the
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131 characters from mainFIRST_TX_CHAR to mainLAST_TX_CHAR. */
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132 #define mainFIRST_TX_CHAR '0'
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133 #define mainLAST_TX_CHAR 'z'
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135 /* Just used to walk through the program memory in order that some random data
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136 can be generated. */
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137 #define mainTOTAL_PROGRAM_MEMORY ( ( unsigned long * ) ( 8 * 1024 ) )
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138 #define mainFIRST_PROGRAM_BYTES ( ( unsigned long * ) 4 )
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140 /* The error routine that is called if the driver library encounters an error. */
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143 __error__(char *pcFilename, unsigned long ulLine)
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148 /*-----------------------------------------------------------*/
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151 * The task that rotates text on the LCD.
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153 static void vLCDTask( void * pvParameters );
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156 * The task that receives the characters from UART 0.
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158 static void vCommsRxTask( void * pvParameters );
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161 * The co-routine that periodically initiates the transmission of the string on
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164 static void vSerialTxCoRoutine( CoRoutineHandle_t xHandle, unsigned portBASE_TYPE uxIndex );
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167 * Writes a string the the LCD.
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169 static void prvWriteString( const char *pcString );
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172 * Initialisation routine for the UART.
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174 static void vSerialInit( void );
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177 * Thread safe write to the PDC.
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179 static void prvPDCWrite( char cAddress, char cData );
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182 * Function to simply set a known value into the general purpose registers
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183 * then read them back to ensure they remain set correctly. An incorrect value
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184 * being indicative of an error in the task switching mechanism.
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186 void prvSetAndCheckRegisters( void );
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189 * Latch the LED that indicates that an error has occurred.
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191 void vSetErrorLED( void );
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194 * Sets up the PLL and ports used by the demo.
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196 static void prvSetupHardware( void );
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198 /*-----------------------------------------------------------*/
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200 /* Error flag set to pdFAIL if an error is encountered in the tasks/co-routines
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201 defined within this file. */
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202 unsigned portBASE_TYPE uxErrorStatus = pdPASS;
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204 /* The next character to transmit. */
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205 static char cNextChar;
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207 /* The queue used to transmit characters from the interrupt to the Comms Rx
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209 static QueueHandle_t xCommsQueue;
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211 /*-----------------------------------------------------------*/
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215 /* Create the queue used to communicate between the UART ISR and the Comms
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217 xCommsQueue = xQueueCreate( mainRX_QUEUE_LEN, sizeof( char ) );
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219 /* Setup the ports used by the demo and the clock. */
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220 prvSetupHardware();
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222 /* Create the co-routines that flash the LED's. */
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223 vStartFlashCoRoutines( mainNUM_FLASH_CO_ROUTINES );
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225 /* Create the co-routine that initiates the transmission of characters
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227 xCoRoutineCreate( vSerialTxCoRoutine, mainTX_CO_ROUTINE_PRIORITY, mainTX_CO_ROUTINE_INDEX );
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229 /* Create the LCD and Comms Rx tasks. */
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230 xTaskCreate( vLCDTask, "LCD", configMINIMAL_STACK_SIZE, NULL, mainLCD_TASK_PRIORITY, NULL );
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231 xTaskCreate( vCommsRxTask, "CMS", configMINIMAL_STACK_SIZE, NULL, mainCOMMS_RX_TASK_PRIORITY, NULL );
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233 /* Start the scheduler running the tasks and co-routines just created. */
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234 vTaskStartScheduler();
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236 /* Should not get here unless we did not have enough memory to start the
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241 /*-----------------------------------------------------------*/
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243 static void prvSetupHardware( void )
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245 /* Setup the PLL. */
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246 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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248 /* Initialise the hardware used to talk to the LCD, LED's and UART. */
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250 vParTestInitialise();
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253 /*-----------------------------------------------------------*/
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255 void vApplicationIdleHook( void )
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257 /* The co-routines are executed in the idle task using the idle task
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261 /* Schedule the co-routines. */
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262 vCoRoutineSchedule();
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264 /* Run the register check function between each co-routine. */
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265 prvSetAndCheckRegisters();
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268 /*-----------------------------------------------------------*/
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270 static void prvWriteString( const char *pcString )
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272 /* Write pcString to the LED, pausing between each character. */
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273 prvPDCWrite(PDC_LCD_CSR, LCD_CLEAR);
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276 vTaskDelay( mainCHAR_WRITE_DELAY );
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277 prvPDCWrite( PDC_LCD_RAM, *pcString );
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281 /*-----------------------------------------------------------*/
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283 void vLCDTask( void * pvParameters )
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285 unsigned portBASE_TYPE uxIndex;
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286 const unsigned char ucCFGData[] = {
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287 0x30, /* Set data bus to 8-bits. */
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290 0x3C, /* Number of lines/font. */
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291 0x08, /* Display off. */
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292 0x01, /* Display clear. */
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293 0x06, /* Entry mode [cursor dir][shift]. */
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294 0x0C /* Display on [display on][curson on][blinking on]. */
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297 /* The strings that are written to the LCD. */
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298 const char *pcStringsToDisplay[] = {
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302 "www.FreeRTOS.org",
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306 /* Configure the LCD. */
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308 while( uxIndex < sizeof( ucCFGData ) )
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310 prvPDCWrite( PDC_LCD_CSR, ucCFGData[ uxIndex ] );
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312 vTaskDelay( mainCHAR_WRITE_DELAY );
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315 /* Turn the LCD Backlight on. */
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316 prvPDCWrite( PDC_CSR, 0x01 );
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318 /* Clear display. */
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319 vTaskDelay( mainCHAR_WRITE_DELAY );
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320 prvPDCWrite( PDC_LCD_CSR, LCD_CLEAR );
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325 /* Display the string on the LCD. */
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326 prvWriteString( pcStringsToDisplay[ uxIndex ] );
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328 /* Move on to the next string - wrapping if necessary. */
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330 if( *( pcStringsToDisplay[ uxIndex ] ) == 0x00 )
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333 /* Longer pause on the last string to be sent. */
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334 vTaskDelay( mainSTRING_WRITE_DELAY * 2 );
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337 /* Wait until it is time to move onto the next string. */
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338 vTaskDelay( mainSTRING_WRITE_DELAY );
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341 /*-----------------------------------------------------------*/
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343 static void vCommsRxTask( void * pvParameters )
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345 static char cRxedChar, cExpectedChar;
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347 /* Set the char we expect to receive to the start of the string. */
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348 cExpectedChar = mainFIRST_TX_CHAR;
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352 /* Wait for a character to be received. */
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353 xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, mainCOMMS_RX_DELAY );
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355 /* Was the character recived (if any) the expected character. */
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356 if( cRxedChar != cExpectedChar )
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358 /* Got an unexpected character. This can sometimes occur when
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359 reseting the system using the debugger leaving characters already
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360 in the UART regsters. */
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361 uxErrorStatus = pdFAIL;
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363 /* Resync by waiting for the end of the current string. */
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364 while( cRxedChar != mainLAST_TX_CHAR )
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366 while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
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369 /* The next expected character is the start of the string again. */
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370 cExpectedChar = mainFIRST_TX_CHAR;
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374 if( cExpectedChar == mainLAST_TX_CHAR )
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376 /* We have reached the end of the string - we now expect to
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377 receive the first character in the string again. The LED is
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378 toggled to indicate that the entire string was received without
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380 vParTestToggleLED( mainCOMMS_RX_LED );
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381 cExpectedChar = mainFIRST_TX_CHAR;
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385 /* We got the expected character, we now expect to receive the
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386 next character in the string. */
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392 /*-----------------------------------------------------------*/
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394 static void vSerialTxCoRoutine( CoRoutineHandle_t xHandle, unsigned portBASE_TYPE uxIndex )
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396 TickType_t xDelayPeriod;
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397 static unsigned long *pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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399 /* Co-routine MUST start with a call to crSTART. */
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400 crSTART( xHandle );
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404 /* Was the previously transmitted string received correctly? */
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405 if( uxErrorStatus != pdPASS )
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407 /* An error was encountered so set the error LED. */
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411 /* The next character to Tx is the first in the string. */
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412 cNextChar = mainFIRST_TX_CHAR;
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414 UARTIntDisable( UART0_BASE, UART_INT_TX );
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416 /* Send the first character. */
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417 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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419 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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422 /* Move the variable to the char to Tx on so the ISR transmits
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423 the next character in the string once this one has completed. */
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426 UARTIntEnable(UART0_BASE, UART_INT_TX);
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428 /* Toggle the LED to show a new string is being transmitted. */
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429 vParTestToggleLED( mainCOMMS_TX_LED );
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431 /* Delay before we start the string off again. A pseudo-random delay
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432 is used as this will provide a better test. */
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433 xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );
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436 if( pulRandomBytes > mainTOTAL_PROGRAM_MEMORY )
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438 pulRandomBytes = mainFIRST_PROGRAM_BYTES;
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441 /* Make sure we don't wait too long... */
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442 xDelayPeriod &= mainMAX_TX_DELAY;
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444 /* ...but we do want to wait. */
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445 if( xDelayPeriod < mainMIN_TX_DELAY )
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447 xDelayPeriod = mainMIN_TX_DELAY;
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450 /* Block for the random(ish) time. */
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451 crDELAY( xHandle, xDelayPeriod );
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454 /* Co-routine MUST end with a call to crEND. */
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457 /*-----------------------------------------------------------*/
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459 static void vSerialInit( void )
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461 /* Enable the UART. GPIOA has already been initialised. */
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462 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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464 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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466 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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468 /* Configure the UART for 8-N-1 operation. */
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469 UARTConfigSet( UART0_BASE, mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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471 /* We dont want to use the fifo. This is for test purposes to generate
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472 as many interrupts as possible. */
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473 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
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475 /* Enable both Rx and Tx interrupts. */
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476 HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
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477 IntEnable( INT_UART0 );
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479 /*-----------------------------------------------------------*/
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481 void vUART_ISR(void)
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483 unsigned long ulStatus;
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485 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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487 /* What caused the interrupt. */
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488 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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490 /* Clear the interrupt. */
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491 UARTIntClear( UART0_BASE, ulStatus );
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493 /* Was an Rx interrpt pending? */
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494 if( ulStatus & UART_INT_RX )
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496 if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
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498 /* Get the char from the buffer and post it onto the queue of
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499 Rxed chars. Posting the character should wake the task that is
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500 blocked on the queue waiting for characters. */
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501 cRxedChar = ( char ) HWREG( UART0_BASE + UART_O_DR );
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502 xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
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506 /* Was a Tx interrupt pending? */
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507 if( ulStatus & UART_INT_TX )
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509 /* Send the next character in the string. We are not using the FIFO. */
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510 if( cNextChar <= mainLAST_TX_CHAR )
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512 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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514 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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520 /* If a task was woken by the character being received then we force
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521 a context switch to occur in case the task is of higher priority than
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522 the currently executing task (i.e. the task that this interrupt
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524 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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526 /*-----------------------------------------------------------*/
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528 static void prvPDCWrite( char cAddress, char cData )
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532 PDCWrite( cAddress, cData );
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536 /*-----------------------------------------------------------*/
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538 void vSetErrorLED( void )
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540 vParTestSetLED( mainCOMMS_FAIL_LED, pdTRUE );
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542 /*-----------------------------------------------------------*/
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544 void prvSetAndCheckRegisters( void )
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546 /* Fill the general purpose registers with known values. */
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550 " add r0, r11, #1 \n"
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551 " add r1, r11, #2 \n"
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552 " add r2, r11, #3 \n"
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553 " add r3, r11, #4 \n"
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554 " add r4, r11, #5 \n"
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555 " add r5, r11, #6 \n"
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556 " add r6, r11, #7 \n"
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557 " add r7, r11, #8 \n"
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558 " add r8, r11, #9 \n"
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559 " add r9, r11, #10 \n"
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560 " add r10, r11, #11 \n"
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561 " add r12, r11, #12"
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564 /* Check the values are as expected. */
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568 " bne set_error_led \n"
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570 " bne set_error_led \n"
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572 " bne set_error_led \n"
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574 " bne set_error_led \n"
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576 " bne set_error_led \n"
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578 " bne set_error_led \n"
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580 " bne set_error_led \n"
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582 " bne set_error_led \n"
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584 " bne set_error_led \n"
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586 " bne set_error_led \n"
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588 " bne set_error_led \n"
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590 " bne set_error_led \n"
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592 " bne set_error_led \n"
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598 "set_error_led: \n"
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600 " ldr r1, vSetErrorLEDConst\n"
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606 "vSetErrorLEDConst: .word vSetErrorLED"
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609 /*-----------------------------------------------------------*/
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