2 FreeRTOS V5.4.1 - Copyright (C) 2009 Real Time Engineers Ltd.
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4 This file is part of the FreeRTOS distribution.
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6 FreeRTOS is free software; you can redistribute it and/or modify it under
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7 the terms of the GNU General Public License (version 2) as published by the
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8 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 without being obliged to provide the
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11 source code for proprietary components outside of the FreeRTOS kernel.
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12 Alternative commercial license and support terms are also available upon
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13 request. See the licensing section of http://www.FreeRTOS.org for full
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16 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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18 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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21 You should have received a copy of the GNU General Public License along
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22 with FreeRTOS; if not, write to the Free Software Foundation, Inc., 59
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23 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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26 ***************************************************************************
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28 * Looking for a quick start? Then check out the FreeRTOS eBook! *
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29 * See http://www.FreeRTOS.org/Documentation for details *
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31 ***************************************************************************
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35 Please ensure to read the configuration and relevant port sections of the
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36 online documentation.
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38 http://www.FreeRTOS.org - Documentation, latest information, license and
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41 http://www.SafeRTOS.com - A version that is certified for use in safety
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44 http://www.OpenRTOS.com - Commercial support, development, porting,
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45 licensing and training services.
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49 * The comms test Rx and Tx task and co-routine. See the comments at the top
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50 * of main.c for full information.
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54 /* Scheduler include files. */
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55 #include "FreeRTOS.h"
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58 #include "croutine.h"
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60 /* Demo application include files. */
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61 #include "partest.h"
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63 /* Library include files. */
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64 #include "DriverLib.h"
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66 /* The LED's toggled by the various tasks. */
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67 #define commsFAIL_LED ( 7 )
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68 #define commsRX_LED ( 6 )
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69 #define commsTX_LED ( 5 )
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71 /* The length of the queue used to pass received characters to the Comms Rx
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73 #define commsRX_QUEUE_LEN ( 5 )
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75 /* The baud rate used by the UART comms tasks/co-routine. */
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76 #define commsBAUD_RATE ( 57600 )
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78 /* FIFO setting for the UART. The FIFO is not used to create a better test. */
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79 #define commsFIFO_SET ( 0x10 )
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81 /* The string that is transmitted on the UART contains sequentially the
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82 characters from commsFIRST_TX_CHAR to commsLAST_TX_CHAR. */
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83 #define commsFIRST_TX_CHAR '0'
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84 #define commsLAST_TX_CHAR 'z'
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86 /* Just used to walk through the program memory in order that some random data
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87 can be generated. */
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88 #define commsTOTAL_PROGRAM_MEMORY ( ( unsigned portLONG * ) ( 8 * 1024 ) )
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89 #define commsFIRST_PROGRAM_BYTES ( ( unsigned portLONG * ) 4 )
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91 /* The time between transmissions of the string on UART 0. This is pseudo
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92 random in order to generate a bit or randomness to when the interrupts occur.*/
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93 #define commsMIN_TX_DELAY ( 40 / portTICK_RATE_MS )
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94 #define commsMAX_TX_DELAY ( ( portTickType ) 0x7f )
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95 #define commsOFFSET_TIME ( ( portTickType ) 3 )
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97 /* The time the Comms Rx task should wait to receive a character. This should
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98 be slightly longer than the time between transmissions. If we do not receive
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99 a character after this time then there must be an error in the transmission or
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100 the timing of the transmission. */
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101 #define commsRX_DELAY ( commsMAX_TX_DELAY + 20 )
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104 static unsigned portBASE_TYPE uxCommsErrorStatus = pdPASS;
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106 /* The queue used to pass characters out of the ISR. */
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107 static xQueueHandle xCommsQueue;
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109 /* The next character to transmit. */
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110 static portCHAR cNextChar;
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112 /*-----------------------------------------------------------*/
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114 void vSerialInit( void )
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116 /* Create the queue used to communicate between the UART ISR and the Comms
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118 xCommsQueue = xQueueCreate( commsRX_QUEUE_LEN, sizeof( portCHAR ) );
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120 /* Enable the UART. GPIOA has already been initialised. */
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121 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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123 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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125 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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127 /* Configure the UART for 8-N-1 operation. */
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128 UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), commsBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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130 /* We dont want to use the fifo. This is for test purposes to generate
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131 as many interrupts as possible. */
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132 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~commsFIFO_SET;
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134 /* Enable both Rx and Tx interrupts. */
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135 HWREG( UART0_BASE + UART_O_IM ) |= ( UART_INT_TX | UART_INT_RX );
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136 IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
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137 IntEnable( INT_UART0 );
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139 /*-----------------------------------------------------------*/
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141 void vSerialTxCoRoutine( xCoRoutineHandle xHandle, unsigned portBASE_TYPE uxIndex )
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143 portTickType xDelayPeriod;
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144 static unsigned portLONG *pulRandomBytes = commsFIRST_PROGRAM_BYTES;
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146 /* Co-routine MUST start with a call to crSTART. */
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147 crSTART( xHandle );
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151 /* Was the previously transmitted string received correctly? */
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152 if( uxCommsErrorStatus != pdPASS )
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154 /* An error was encountered so set the error LED. */
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155 vParTestSetLED( commsFAIL_LED, pdTRUE );
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158 /* The next character to Tx is the first in the string. */
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159 cNextChar = commsFIRST_TX_CHAR;
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161 UARTIntDisable( UART0_BASE, UART_INT_TX );
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163 /* Send the first character. */
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164 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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166 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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169 /* Move the variable to the char to Tx on so the ISR transmits
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170 the next character in the string once this one has completed. */
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173 UARTIntEnable(UART0_BASE, UART_INT_TX);
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175 /* Toggle the LED to show a new string is being transmitted. */
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176 vParTestToggleLED( commsTX_LED );
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178 /* Delay before we start the string off again. A pseudo-random delay
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179 is used as this will provide a better test. */
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180 xDelayPeriod = xTaskGetTickCount() + ( *pulRandomBytes );
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183 if( pulRandomBytes > commsTOTAL_PROGRAM_MEMORY )
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185 pulRandomBytes = commsFIRST_PROGRAM_BYTES;
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188 /* Make sure we don't wait too long... */
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189 xDelayPeriod &= commsMAX_TX_DELAY;
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191 /* ...but we do want to wait. */
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192 if( xDelayPeriod < commsMIN_TX_DELAY )
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194 xDelayPeriod = commsMIN_TX_DELAY;
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197 /* Block for the random(ish) time. */
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198 crDELAY( xHandle, xDelayPeriod );
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201 /* Co-routine MUST end with a call to crEND. */
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204 /*-----------------------------------------------------------*/
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206 void vUART_ISR( void )
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208 unsigned portLONG ulStatus;
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209 portCHAR cRxedChar;
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210 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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212 /* What caused the interrupt. */
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213 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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215 /* Clear the interrupt. */
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216 UARTIntClear( UART0_BASE, ulStatus );
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218 /* Was an Rx interrpt pending? */
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219 if( ulStatus & UART_INT_RX )
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221 if( ( HWREG(UART0_BASE + UART_O_FR ) & UART_FR_RXFF ) )
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223 /* Get the char from the buffer and post it onto the queue of
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224 Rxed chars. Posting the character should wake the task that is
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225 blocked on the queue waiting for characters. */
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226 cRxedChar = ( portCHAR ) HWREG( UART0_BASE + UART_O_DR );
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227 xQueueSendFromISR( xCommsQueue, &cRxedChar, &xHigherPriorityTaskWoken );
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231 /* Was a Tx interrupt pending? */
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232 if( ulStatus & UART_INT_TX )
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234 /* Send the next character in the string. We are not using the FIFO. */
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235 if( cNextChar <= commsLAST_TX_CHAR )
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237 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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239 HWREG( UART0_BASE + UART_O_DR ) = cNextChar;
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245 /* If a task was woken by the character being received then we force
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246 a context switch to occur in case the task is of higher priority than
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247 the currently executing task (i.e. the task that this interrupt
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249 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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251 /*-----------------------------------------------------------*/
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253 void vCommsRxTask( void * pvParameters )
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255 static portCHAR cRxedChar, cExpectedChar;
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257 /* Set the char we expect to receive to the start of the string. */
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258 cExpectedChar = commsFIRST_TX_CHAR;
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262 /* Wait for a character to be received. */
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263 xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, commsRX_DELAY );
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265 /* Was the character recived (if any) the expected character. */
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266 if( cRxedChar != cExpectedChar )
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268 /* Got an unexpected character. This can sometimes occur when
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269 reseting the system using the debugger leaving characters already
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270 in the UART regsters. */
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271 uxCommsErrorStatus = pdFAIL;
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273 /* Resync by waiting for the end of the current string. */
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274 while( cRxedChar != commsLAST_TX_CHAR )
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276 while( !xQueueReceive( xCommsQueue, ( void * ) &cRxedChar, portMAX_DELAY ) );
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279 /* The next expected character is the start of the string again. */
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280 cExpectedChar = commsFIRST_TX_CHAR;
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284 if( cExpectedChar == commsLAST_TX_CHAR )
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286 /* We have reached the end of the string - we now expect to
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287 receive the first character in the string again. The LED is
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288 toggled to indicate that the entire string was received without
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290 vParTestToggleLED( commsRX_LED );
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291 cExpectedChar = commsFIRST_TX_CHAR;
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295 /* We got the expected character, we now expect to receive the
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296 next character in the string. */
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302 /*-----------------------------------------------------------*/
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304 unsigned portBASE_TYPE uxGetCommsStatus( void )
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306 return uxCommsErrorStatus;
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