2 FreeRTOS V6.1.0 - Copyright (C) 2010 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 * This file only supports UART A0 in loopback mode, and has not been tested
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58 * for real UART operation (only loopback mode) so is not guaranteed to have
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59 * a correct baud rate configuration.
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62 /* Standard includes. */
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65 /* Scheduler includes. */
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66 #include "FreeRTOS.h"
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70 /* Demo application includes. */
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74 #include "hal_usb.h"
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76 /* Constants required to setup the hardware. */
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77 #define serTX_AND_RX ( ( unsigned portCHAR ) 0x03 )
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79 /* Misc. constants. */
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80 #define serNO_BLOCK ( ( portTickType ) 0 )
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82 /* The queue used to hold received characters. */
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83 static xQueueHandle xRxedChars;
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85 /* The queue used to hold characters waiting transmission. */
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86 static xQueueHandle xCharsForTx;
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88 /*-----------------------------------------------------------*/
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90 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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92 unsigned portLONG ulBaudRateCount;
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94 /* Initialise the hardware. */
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96 /* Generate the baud rate constants for the wanted baud rate. */
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97 ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;
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99 portENTER_CRITICAL();
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101 /* Create the queues used by the com test task. */
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102 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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103 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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105 USB_PORT_SEL |= USB_PIN_RXD + USB_PIN_TXD;
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106 USB_PORT_DIR |= USB_PIN_TXD;
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107 USB_PORT_DIR &= ~USB_PIN_RXD;
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110 UCA1CTL1 |= UCSWRST;
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113 UCA1CTL1 = UCSSEL0 | UCSSEL1;
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115 /* Setup baud rate low byte. */
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116 UCA1BR0 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );
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118 /* Setup baud rate high byte. */
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119 ulBaudRateCount >>= 8UL;
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120 UCA1BR1 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );
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122 /* UCLISTEN sets loopback mode! */
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123 UCA1STAT = UCLISTEN;
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125 /* Enable interrupts. */
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128 /* Take out of reset. */
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129 UCA1CTL1 &= ~UCSWRST;
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131 portEXIT_CRITICAL();
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133 /* Unlike other ports, this serial code does not allow for more than one
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134 com port. We therefore don't return a pointer to a port structure and can
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135 instead just return NULL. */
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138 /*-----------------------------------------------------------*/
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140 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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142 /* Get the next character from the buffer. Return false if no characters
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143 are available, or arrive before xBlockTime expires. */
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144 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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153 /*-----------------------------------------------------------*/
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155 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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157 signed portBASE_TYPE xReturn;
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159 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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164 /*-----------------------------------------------------------*/
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166 #pragma vector=USCI_A1_VECTOR
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167 static __interrupt void prvUSCI_A0_ISR( void )
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169 signed portCHAR cChar;
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170 portBASE_TYPE xTaskWoken = pdFALSE;
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171 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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173 while( ( UCA1IFG & UCRXIFG ) != 0 )
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175 /* Get the character from the UART and post it on the queue of Rxed
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178 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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181 /* If there is a Tx interrupt pending and the tx interrupts are enabled. */
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182 if( ( UCA1IFG & UCTXIFG ) != 0 )
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184 /* The previous character has been transmitted. See if there are any
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185 further characters waiting transmission. */
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186 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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188 /* There was another character queued - transmit it now. */
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193 /* There were no other characters to transmit - disable the Tx
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199 __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
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200 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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