2 FreeRTOS.org V5.3.0 - 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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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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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 * The comms test Rx and Tx task and co-routine. See the comments at the top
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54 * of main.c for full information.
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58 /* Scheduler include files. */
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59 #include "FreeRTOS.h"
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62 #include "croutine.h"
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64 /* Demo application include files. */
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65 #include "partest.h"
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67 /* Library include files. */
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68 #include "DriverLib.h"
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70 /* The LED's toggled by the various tasks. */
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71 #define commsFAIL_LED ( 7 )
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72 #define commsRX_LED ( 6 )
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73 #define commsTX_LED ( 5 )
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75 /* The length of the queue used to pass received characters to the Comms Rx
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77 #define commsRX_QUEUE_LEN ( 5 )
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79 /* The baud rate used by the UART comms tasks/co-routine. */
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80 #define commsBAUD_RATE ( 57600 )
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82 /* FIFO setting for the UART. The FIFO is not used to create a better test. */
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83 #define commsFIFO_SET ( 0x10 )
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85 /* The string that is transmitted on the UART contains sequentially the
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86 characters from commsFIRST_TX_CHAR to commsLAST_TX_CHAR. */
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87 #define commsFIRST_TX_CHAR '0'
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88 #define commsLAST_TX_CHAR 'z'
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90 /* Just used to walk through the program memory in order that some random data
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91 can be generated. */
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92 #define commsTOTAL_PROGRAM_MEMORY ( ( unsigned portLONG * ) ( 8 * 1024 ) )
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93 #define commsFIRST_PROGRAM_BYTES ( ( unsigned portLONG * ) 4 )
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95 /* The time between transmissions of the string on UART 0. This is pseudo
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96 random in order to generate a bit or randomness to when the interrupts occur.*/
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97 #define commsMIN_TX_DELAY ( 40 / portTICK_RATE_MS )
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98 #define commsMAX_TX_DELAY ( ( portTickType ) 0x7f )
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99 #define commsOFFSET_TIME ( ( portTickType ) 3 )
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101 /* The time the Comms Rx task should wait to receive a character. This should
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102 be slightly longer than the time between transmissions. If we do not receive
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103 a character after this time then there must be an error in the transmission or
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104 the timing of the transmission. */
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105 #define commsRX_DELAY ( commsMAX_TX_DELAY + 20 )
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108 static unsigned portBASE_TYPE uxCommsErrorStatus = pdPASS;
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110 /* The queue used to pass characters out of the ISR. */
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111 static xQueueHandle xCommsQueue;
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113 /* The next character to transmit. */
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114 static portCHAR cNextChar;
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116 /*-----------------------------------------------------------*/
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118 void vSerialInit( void )
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120 /* Create the queue used to communicate between the UART ISR and the Comms
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122 xCommsQueue = xQueueCreate( commsRX_QUEUE_LEN, sizeof( portCHAR ) );
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124 /* Enable the UART. GPIOA has already been initialised. */
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125 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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127 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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129 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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131 /* Configure the UART for 8-N-1 operation. */
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132 UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), commsBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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134 /* We dont want to use the fifo. This is for test purposes to generate
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135 as many interrupts as possible. */
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136 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~commsFIFO_SET;
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138 /* Enable both Rx and Tx interrupts. */
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139 HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
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140 IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
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141 IntEnable( INT_UART0 );
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143 /*-----------------------------------------------------------*/
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145 void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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147 portTickType xDelayPeriod;
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148 static unsigned portLONG *pulRandomBytes = commsFIRST_PROGRAM_BYTES;
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150 /* Co-routine MUST start with a call to crSTART. */
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151 crSTART( xHandle );
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155 /* Was the previously transmitted string received correctly? */
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156 if( uxCommsErrorStatus != pdPASS )
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158 /* An error was encountered so set the error LED. */
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159 vParTestSetLED( commsFAIL_LED, pdTRUE );
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162 /* The next character to Tx is the first in the string. */
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163 cNextChar = commsFIRST_TX_CHAR;
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165 UARTIntDisable( UART0_BASE, UART_INT_TX );
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167 /* Send the first character. */
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168 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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170 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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173 /* Move the variable to the char to Tx on so the ISR transmits
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174 the next character in the string once this one has completed. */
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177 UARTIntEnable(UART0_BASE, UART_INT_TX);
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179 /* Toggle the LED to show a new string is being transmitted. */
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180 vParTestToggleLED( commsTX_LED );
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182 /* Delay before we start the string off again. A pseudo-random delay
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183 is used as this will provide a better test. */
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184 xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );
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187 if( pulRandomBytes > commsTOTAL_PROGRAM_MEMORY )
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189 pulRandomBytes = commsFIRST_PROGRAM_BYTES;
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192 /* Make sure we don't wait too long... */
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193 xDelayPeriod &= commsMAX_TX_DELAY;
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195 /* ...but we do want to wait. */
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196 if( xDelayPeriod < commsMIN_TX_DELAY )
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198 xDelayPeriod = commsMIN_TX_DELAY;
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201 /* Block for the random(ish) time. */
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202 crDELAY( xHandle, xDelayPeriod );
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205 /* Co-routine MUST end with a call to crEND. */
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208 /*-----------------------------------------------------------*/
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210 void vUART_ISR( void )
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212 unsigned portLONG ulStatus;
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213 portCHAR cRxedChar;
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214 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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216 /* What caused the interrupt. */
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217 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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219 /* Clear the interrupt. */
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220 UARTIntClear( UART0_BASE, ulStatus );
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222 /* Was an Rx interrpt pending? */
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223 if( ulStatus & UART_INT_RX )
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225 if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
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227 /* Get the char from the buffer and post it onto the queue of
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228 Rxed chars. Posting the character should wake the task that is
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229 blocked on the queue waiting for characters. */
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230 cRxedChar = ( portCHAR ) HWREG( UART0_BASE + UART_O_DR );
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231 xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
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235 /* Was a Tx interrupt pending? */
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236 if( ulStatus & UART_INT_TX )
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238 /* Send the next character in the string. We are not using the FIFO. */
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239 if( cNextChar <= commsLAST_TX_CHAR )
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241 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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243 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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249 /* If a task was woken by the character being received then we force
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250 a context switch to occur in case the task is of higher priority than
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251 the currently executing task (i.e. the task that this interrupt
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253 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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255 /*-----------------------------------------------------------*/
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257 void vCommsRxTask( void * pvParameters )
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259 static portCHAR cRxedChar, cExpectedChar;
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261 /* Set the char we expect to receive to the start of the string. */
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262 cExpectedChar = commsFIRST_TX_CHAR;
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266 /* Wait for a character to be received. */
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267 xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, commsRX_DELAY );
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269 /* Was the character recived (if any) the expected character. */
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270 if( cRxedChar != cExpectedChar )
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272 /* Got an unexpected character. This can sometimes occur when
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273 reseting the system using the debugger leaving characters already
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274 in the UART regsters. */
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275 uxCommsErrorStatus = pdFAIL;
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277 /* Resync by waiting for the end of the current string. */
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278 while( cRxedChar != commsLAST_TX_CHAR )
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280 while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
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283 /* The next expected character is the start of the string again. */
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284 cExpectedChar = commsFIRST_TX_CHAR;
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288 if( cExpectedChar == commsLAST_TX_CHAR )
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290 /* We have reached the end of the string - we now expect to
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291 receive the first character in the string again. The LED is
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292 toggled to indicate that the entire string was received without
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294 vParTestToggleLED( commsRX_LED );
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295 cExpectedChar = commsFIRST_TX_CHAR;
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299 /* We got the expected character, we now expect to receive the
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300 next character in the string. */
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306 /*-----------------------------------------------------------*/
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308 unsigned portBASE_TYPE uxGetCommsStatus( void )
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310 return uxCommsErrorStatus;
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