2 FreeRTOS V8.2.2 - Copyright (C) 2015 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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72 + ISRcode removed. Is now pulled inline to reduce stack-usage.
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77 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
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79 /* Scheduler header files. */
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80 #include "FreeRTOS.h"
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86 /* Hardware pin definitions. */
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87 #define serTX_PIN bTRC6
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88 #define serRX_PIN bTRC7
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90 /* Bit/register definitions. */
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91 #define serINPUT ( 1 )
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92 #define serOUTPUT ( 0 )
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93 #define serINTERRUPT_ENABLED ( 1 )
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95 /* All ISR's use the PIC18 low priority interrupt. */
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96 #define serLOW_PRIORITY ( 0 )
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98 /*-----------------------------------------------------------*/
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100 /* Queues to interface between comms API and interrupt routines. */
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101 QueueHandle_t xRxedChars;
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102 QueueHandle_t xCharsForTx;
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103 portBASE_TYPE xHigherPriorityTaskWoken;
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105 /*-----------------------------------------------------------*/
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107 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned char ucQueueLength )
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109 unsigned short usSPBRG;
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111 /* Create the queues used by the ISR's to interface to tasks. */
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112 xRxedChars = xQueueCreate( ucQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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113 xCharsForTx = xQueueCreate( ucQueueLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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115 portENTER_CRITICAL();
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117 /* Setup the IO pins to enable the USART IO. */
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118 serTX_PIN = serINPUT; // YES really! See datasheet
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119 serRX_PIN = serINPUT;
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121 /* Set the TX config register. */
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122 TXSTA = 0b00100000;
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123 // ||||||||--bit0: TX9D = n/a
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124 // |||||||---bit1: TRMT = ReadOnly
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125 // ||||||----bit2: BRGH = High speed
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126 // |||||-----bit3: SENDB = n/a
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127 // ||||------bit4: SYNC = Asynchronous mode
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128 // |||-------bit5: TXEN = Transmit enable
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129 // ||--------bit6: TX9 = 8-bit transmission
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130 // |---------bit7: CSRC = n/a
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132 /* Set the Receive config register. */
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133 RCSTA = 0b10010000;
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134 // ||||||||--bit0: RX9D = ReadOnly
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135 // |||||||---bit1: OERR = ReadOnly
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136 // ||||||----bit2: FERR = ReadOnly
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137 // |||||-----bit3: ADDEN = n/a
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138 // ||||------bit4: CREN = Enable receiver
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139 // |||-------bit5: SREN = n/a
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140 // ||--------bit6: RX9 = 8-bit reception
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141 // |---------bit7: SPEN = Serial port enabled
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143 /* Calculate the baud rate generator value.
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144 We use low-speed (BRGH=0), the formula is
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145 SPBRG = ( ( FOSC / Desired Baud Rate ) / 64 ) - 1 */
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146 usSPBRG = ( ( APROCFREQ / ulWantedBaud ) / 64 ) - 1;
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147 if( usSPBRG > 255 )
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156 /* Set the serial interrupts to use the same priority as the tick. */
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157 bTXIP = serLOW_PRIORITY;
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158 bRCIP = serLOW_PRIORITY;
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160 /* Enable the Rx interrupt now, the Tx interrupt will get enabled when
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161 we have data to send. */
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162 bRCIE = serINTERRUPT_ENABLED;
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164 portEXIT_CRITICAL();
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166 /* Unlike other ports, this serial code does not allow for more than one
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167 com port. We therefore don't return a pointer to a port structure and
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168 can instead just return NULL. */
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171 /*-----------------------------------------------------------*/
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173 xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned char ucBufferLength )
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175 /* This is not implemented in this port.
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176 Use xSerialPortInitMinimal() instead. */
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179 /*-----------------------------------------------------------*/
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181 portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, char *pcRxedChar, TickType_t xBlockTime )
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183 /* Get the next character from the buffer. Return false if no characters
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184 are available, or arrive before xBlockTime expires. */
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185 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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187 return ( char ) pdTRUE;
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190 return ( char ) pdFALSE;
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192 /*-----------------------------------------------------------*/
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194 portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, char cOutChar, TickType_t xBlockTime )
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196 /* Return false if after the block time there is no room on the Tx queue. */
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197 if( xQueueSend( xCharsForTx, ( const void * ) &cOutChar, xBlockTime ) != ( char ) pdPASS )
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202 /* Turn interrupt on - ensure the compiler only generates a single
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203 instruction for this. */
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204 bTXIE = serINTERRUPT_ENABLED;
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208 /*-----------------------------------------------------------*/
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210 void vSerialClose( xComPortHandle xPort )
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212 /* Not implemented for this port.
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213 To implement, turn off the interrupts and delete the memory
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214 allocated to the queues. */
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