2 FreeRTOS V6.1.1 - Copyright (C) 2011 Real Time Engineers Ltd.
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4 ***************************************************************************
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8 * + New to FreeRTOS, *
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9 * + Wanting to learn FreeRTOS or multitasking in general quickly *
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10 * + Looking for basic training, *
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11 * + Wanting to improve your FreeRTOS skills and productivity *
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13 * then take a look at the FreeRTOS books - available as PDF or paperback *
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15 * "Using the FreeRTOS Real Time Kernel - a Practical Guide" *
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16 * http://www.FreeRTOS.org/Documentation *
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18 * A pdf reference manual is also available. Both are usually delivered *
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19 * to your inbox within 20 minutes to two hours when purchased between 8am *
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20 * and 8pm GMT (although please allow up to 24 hours in case of *
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21 * exceptional circumstances). Thank you for your support! *
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23 ***************************************************************************
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25 This file is part of the FreeRTOS distribution.
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27 FreeRTOS is free software; you can redistribute it and/or modify it under
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28 the terms of the GNU General Public License (version 2) as published by the
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29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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30 ***NOTE*** The exception to the GPL is included to allow you to distribute
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31 a combined work that includes FreeRTOS without being obliged to provide the
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32 source code for proprietary components outside of the FreeRTOS kernel.
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33 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT
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34 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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35 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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36 more details. You should have received a copy of the GNU General Public
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37 License and the FreeRTOS license exception along with FreeRTOS; if not it
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38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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39 by writing to Richard Barry, contact details for whom are available on the
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44 http://www.FreeRTOS.org - Documentation, latest information, license and
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47 http://www.SafeRTOS.com - A version that is certified for use in safety
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50 http://www.OpenRTOS.com - Commercial support, development, porting,
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51 licensing and training services.
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55 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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57 NOTE: This driver is primarily to test the scheduler functionality. It does
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58 not effectively use the buffers or DMA and is therefore not intended to be
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59 an example of an efficient driver. */
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61 /* Standard include file. */
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64 /* Scheduler include files. */
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65 #include "FreeRTOS.h"
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69 /* Demo app include files. */
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72 /* Hardware setup. */
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75 #define serLOW_SPEED 0
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76 #define serONE_STOP_BIT 0
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77 #define serEIGHT_DATA_BITS_NO_PARITY 0
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78 #define serNORMAL_IDLE_STATE 0
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79 #define serAUTO_BAUD_OFF 0
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80 #define serLOOPBACK_OFF 0
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81 #define serWAKE_UP_DISABLE 0
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82 #define serNO_HARDWARE_FLOW_CONTROL 0
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83 #define serSTANDARD_IO 0
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84 #define serNO_IRDA 0
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85 #define serCONTINUE_IN_IDLE_MODE 0
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86 #define serUART_ENABLED 1
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87 #define serINTERRUPT_ON_SINGLE_CHAR 0
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88 #define serTX_ENABLE 1
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89 #define serINTERRUPT_ENABLE 1
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90 #define serINTERRUPT_DISABLE 0
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91 #define serCLEAR_FLAG 0
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92 #define serSET_FLAG 1
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95 /* The queues used to communicate between tasks and ISR's. */
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96 static xQueueHandle xRxedChars;
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97 static xQueueHandle xCharsForTx;
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99 static portBASE_TYPE xTxHasEnded;
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100 /*-----------------------------------------------------------*/
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102 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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106 /* Create the queues used by the com test task. */
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107 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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108 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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110 /* Setup the UART. */
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111 U2MODEbits.BRGH = serLOW_SPEED;
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112 U2MODEbits.STSEL = serONE_STOP_BIT;
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113 U2MODEbits.PDSEL = serEIGHT_DATA_BITS_NO_PARITY;
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114 U2MODEbits.ABAUD = serAUTO_BAUD_OFF;
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115 U2MODEbits.LPBACK = serLOOPBACK_OFF;
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116 U2MODEbits.WAKE = serWAKE_UP_DISABLE;
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117 U2MODEbits.UEN = serNO_HARDWARE_FLOW_CONTROL;
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118 U2MODEbits.IREN = serNO_IRDA;
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119 U2MODEbits.USIDL = serCONTINUE_IN_IDLE_MODE;
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120 U2MODEbits.UARTEN = serUART_ENABLED;
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122 U2BRG = (unsigned short)(( (float)configCPU_CLOCK_HZ / ( (float)16 * (float)ulWantedBaud ) ) - (float)0.5);
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124 U2STAbits.URXISEL = serINTERRUPT_ON_SINGLE_CHAR;
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125 U2STAbits.UTXEN = serTX_ENABLE;
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126 U2STAbits.UTXINV = serNORMAL_IDLE_STATE;
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127 U2STAbits.UTXISEL0 = serINTERRUPT_ON_SINGLE_CHAR;
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128 U2STAbits.UTXISEL1 = serINTERRUPT_ON_SINGLE_CHAR;
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130 /* It is assumed that this function is called prior to the scheduler being
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131 started. Therefore interrupts must not be allowed to occur yet as they
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132 may attempt to perform a context switch. */
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133 portDISABLE_INTERRUPTS();
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135 IFS1bits.U2RXIF = serCLEAR_FLAG;
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136 IFS1bits.U2TXIF = serCLEAR_FLAG;
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137 IPC7bits.U2RXIP = configKERNEL_INTERRUPT_PRIORITY;
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138 IPC7bits.U2TXIP = configKERNEL_INTERRUPT_PRIORITY;
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139 IEC1bits.U2TXIE = serINTERRUPT_ENABLE;
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140 IEC1bits.U2RXIE = serINTERRUPT_ENABLE;
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142 /* Clear the Rx buffer. */
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143 while( U2STAbits.URXDA == serSET_FLAG )
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148 xTxHasEnded = pdTRUE;
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152 /*-----------------------------------------------------------*/
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154 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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156 /* Only one port is supported. */
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159 /* Get the next character from the buffer. Return false if no characters
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160 are available or arrive before xBlockTime expires. */
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161 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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170 /*-----------------------------------------------------------*/
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172 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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174 /* Only one port is supported. */
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177 /* Return false if after the block time there is no room on the Tx queue. */
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178 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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183 /* A critical section should not be required as xTxHasEnded will not be
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184 written to by the ISR if it is already 0 (is this correct?). */
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187 xTxHasEnded = pdFALSE;
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188 IFS1bits.U2TXIF = serSET_FLAG;
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193 /*-----------------------------------------------------------*/
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195 void vSerialClose( xComPortHandle xPort )
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198 /*-----------------------------------------------------------*/
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200 void __attribute__((__interrupt__, auto_psv)) _U2RXInterrupt( void )
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203 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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205 /* Get the character and post it on the queue of Rxed characters.
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206 If the post causes a task to wake force a context switch as the woken task
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207 may have a higher priority than the task we have interrupted. */
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208 IFS1bits.U2RXIF = serCLEAR_FLAG;
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209 while( U2STAbits.URXDA )
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212 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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215 if( xHigherPriorityTaskWoken != pdFALSE )
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220 /*-----------------------------------------------------------*/
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222 void __attribute__((__interrupt__, auto_psv)) _U2TXInterrupt( void )
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225 portBASE_TYPE xTaskWoken = pdFALSE;
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227 /* If the transmit buffer is full we cannot get the next character.
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228 Another interrupt will occur the next time there is space so this does
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230 IFS1bits.U2TXIF = serCLEAR_FLAG;
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231 while( !( U2STAbits.UTXBF ) )
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233 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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235 /* Send the next character queued for Tx. */
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240 /* Queue empty, nothing to send. */
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241 xTxHasEnded = pdTRUE;
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246 if( xTaskWoken != pdFALSE )
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