2 FreeRTOS V7.4.1 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not it can be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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77 * This version of comtest. c is for use on systems that have limited stack
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78 * space and no display facilities. The complete version can be found in
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79 * the Demo/Common/Full directory.
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81 * Creates two tasks that operate on an interrupt driven serial port. A
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82 * loopback connector should be used so that everything that is transmitted is
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83 * also received. The serial port does not use any flow control. On a
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84 * standard 9way 'D' connector pins two and three should be connected together.
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86 * The first task posts a sequence of characters to the Tx queue, toggling an
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87 * LED on each successful post. At the end of the sequence it sleeps for a
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88 * pseudo-random period before resending the same sequence.
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90 * The UART Tx end interrupt is enabled whenever data is available in the Tx
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91 * queue. The Tx end ISR removes a single character from the Tx queue and
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92 * passes it to the UART for transmission.
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94 * The second task blocks on the Rx queue waiting for a character to become
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95 * available. When the UART Rx end interrupt receives a character it places
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96 * it in the Rx queue, waking the second task. The second task checks that the
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97 * characters removed from the Rx queue form the same sequence as those posted
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98 * to the Tx queue, and toggles an LED for each correct character.
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100 * The receiving task is spawned with a higher priority than the transmitting
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101 * task. The receiver will therefore wake every time a character is
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102 * transmitted so neither the Tx or Rx queue should ever hold more than a few
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107 /* Scheduler include files. */
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108 #include <stdlib.h>
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109 #include "FreeRTOS.h"
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112 /* Demo program include files. */
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113 #include "demo_serial.h"
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114 #include "comtest2.h"
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115 #include "partest.h"
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117 #define comSTACK_SIZE configMINIMAL_STACK_SIZE
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118 #define comTX_LED_OFFSET ( 0 )
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119 #define comRX_LED_OFFSET ( 1 )
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120 #define comTOTAL_PERMISSIBLE_ERRORS ( 2 )
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122 /* The Tx task will transmit the sequence of characters at a pseudo random
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123 interval. This is the maximum and minimum block time between sends. */
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124 #define comTX_MAX_BLOCK_TIME ( ( portTickType ) 0x96 )
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125 #define comTX_MIN_BLOCK_TIME ( ( portTickType ) 0x32 )
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126 #define comOFFSET_TIME ( ( portTickType ) 3 )
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128 /* We should find that each character can be queued for Tx immediately and we
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129 don't have to block to send. */
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130 #define comNO_BLOCK ( ( portTickType ) 0 )
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132 /* The Rx task will block on the Rx queue for a long period. */
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133 #define comRX_BLOCK_TIME ( ( portTickType ) 0xffff )
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135 /* The sequence transmitted is from comFIRST_BYTE to and including comLAST_BYTE. */
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136 #define comFIRST_BYTE ( 'A' )
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137 #define comLAST_BYTE ( 'X' )
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139 #define comBUFFER_LEN ( ( unsigned portBASE_TYPE ) ( comLAST_BYTE - comFIRST_BYTE ) + ( unsigned portBASE_TYPE ) 1 )
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140 #define comINITIAL_RX_COUNT_VALUE ( 0 )
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142 /* Handle to the com port used by both tasks. */
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143 static xComPortHandle xPort = NULL;
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145 /* The transmit task as described at the top of the file. */
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146 static portTASK_FUNCTION_PROTO( vComTxTask, pvParameters );
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148 /* The receive task as described at the top of the file. */
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149 static portTASK_FUNCTION_PROTO( vComRxTask, pvParameters );
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151 /* The LED that should be toggled by the Rx and Tx tasks. The Rx task will
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152 toggle LED ( uxBaseLED + comRX_LED_OFFSET). The Tx task will toggle LED
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153 ( uxBaseLED + comTX_LED_OFFSET ). */
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154 static unsigned portBASE_TYPE uxBaseLED = 0;
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156 /* Check variable used to ensure no error have occurred. The Rx task will
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157 increment this variable after every successfully received sequence. If at any
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158 time the sequence is incorrect the the variable will stop being incremented. */
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159 static volatile unsigned portBASE_TYPE uxRxLoops = comINITIAL_RX_COUNT_VALUE;
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161 /*-----------------------------------------------------------*/
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163 void vAltStartComTestTasks( unsigned portBASE_TYPE uxPriority, unsigned long ulBaudRate, unsigned portBASE_TYPE uxLED )
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165 /* Initialise the com port then spawn the Rx and Tx tasks. */
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167 xSerialPortInitMinimal( ulBaudRate, comBUFFER_LEN );
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169 /* The Tx task is spawned with a lower priority than the Rx task. */
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170 xTaskCreate( vComTxTask, ( signed char * ) "COMTx", comSTACK_SIZE, NULL, uxPriority - 1, ( xTaskHandle * ) NULL );
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171 xTaskCreate( vComRxTask, ( signed char * ) "COMRx", comSTACK_SIZE, NULL, uxPriority, ( xTaskHandle * ) NULL );
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173 /*-----------------------------------------------------------*/
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175 static portTASK_FUNCTION( vComTxTask, pvParameters )
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177 signed char cByteToSend;
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178 portTickType xTimeToWait;
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180 /* Just to stop compiler warnings. */
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181 ( void ) pvParameters;
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185 /* Simply transmit a sequence of characters from comFIRST_BYTE to
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187 for( cByteToSend = comFIRST_BYTE; cByteToSend <= comLAST_BYTE; cByteToSend++ )
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189 if( xSerialPutChar( xPort, cByteToSend, comNO_BLOCK ) == pdPASS )
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191 vParTestToggleLED( uxBaseLED + comTX_LED_OFFSET );
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195 /* Turn the LED off while we are not doing anything. */
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196 vParTestSetLED( uxBaseLED + comTX_LED_OFFSET, pdFALSE );
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198 /* We have posted all the characters in the string - wait before
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199 re-sending. Wait a pseudo-random time as this will provide a better
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201 xTimeToWait = xTaskGetTickCount() + comOFFSET_TIME;
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203 /* Make sure we don't wait too long... */
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204 xTimeToWait %= comTX_MAX_BLOCK_TIME;
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206 /* ...but we do want to wait. */
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207 if( xTimeToWait < comTX_MIN_BLOCK_TIME )
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209 xTimeToWait = comTX_MIN_BLOCK_TIME;
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212 vTaskDelay( xTimeToWait );
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214 } /*lint !e715 !e818 pvParameters is required for a task function even if it is not referenced. */
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215 /*-----------------------------------------------------------*/
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217 static portTASK_FUNCTION( vComRxTask, pvParameters )
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219 signed char cExpectedByte, cByteRxed;
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220 portBASE_TYPE xResyncRequired = pdFALSE, xErrorOccurred = pdFALSE;
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222 /* Just to stop compiler warnings. */
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223 ( void ) pvParameters;
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227 /* We expect to receive the characters from comFIRST_BYTE to
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228 comLAST_BYTE in an incrementing order. Loop to receive each byte. */
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229 for( cExpectedByte = comFIRST_BYTE; cExpectedByte <= comLAST_BYTE; cExpectedByte++ )
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231 /* Block on the queue that contains received bytes until a byte is
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233 if( xSerialGetChar( xPort, &cByteRxed, comRX_BLOCK_TIME ) )
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235 /* Was this the byte we were expecting? If so, toggle the LED,
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236 otherwise we are out on sync and should break out of the loop
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237 until the expected character sequence is about to restart. */
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238 if( cByteRxed == cExpectedByte )
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240 vParTestToggleLED( uxBaseLED + comRX_LED_OFFSET );
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244 xResyncRequired = pdTRUE;
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245 break; /*lint !e960 Non-switch break allowed. */
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250 /* Turn the LED off while we are not doing anything. */
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251 vParTestSetLED( uxBaseLED + comRX_LED_OFFSET, pdFALSE );
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253 /* Did we break out of the loop because the characters were received in
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254 an unexpected order? If so wait here until the character sequence is
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255 about to restart. */
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256 if( xResyncRequired == pdTRUE )
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258 while( cByteRxed != comLAST_BYTE )
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260 /* Block until the next char is available. */
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261 xSerialGetChar( xPort, &cByteRxed, comRX_BLOCK_TIME );
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264 /* Note that an error occurred which caused us to have to resync.
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265 We use this to stop incrementing the loop counter so
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266 sAreComTestTasksStillRunning() will return false - indicating an
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270 /* We have now resynced with the Tx task and can continue. */
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271 xResyncRequired = pdFALSE;
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275 if( xErrorOccurred < comTOTAL_PERMISSIBLE_ERRORS )
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277 /* Increment the count of successful loops. As error
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278 occurring (i.e. an unexpected character being received) will
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279 prevent this counter being incremented for the rest of the
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280 execution. Don't worry about mutual exclusion on this
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281 variable - it doesn't really matter as we just want it
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287 } /*lint !e715 !e818 pvParameters is required for a task function even if it is not referenced. */
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288 /*-----------------------------------------------------------*/
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290 portBASE_TYPE xAreComTestTasksStillRunning( void )
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292 portBASE_TYPE xReturn;
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294 /* If the count of successful reception loops has not changed than at
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295 some time an error occurred (i.e. a character was received out of sequence)
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296 and we will return false. */
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297 if( uxRxLoops == comINITIAL_RX_COUNT_VALUE )
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306 /* Reset the count of successful Rx loops. When this function is called
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307 again we expect this to have been incremented. */
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308 uxRxLoops = comINITIAL_RX_COUNT_VALUE;
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