2 FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 ***************************************************************************
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29 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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31 * This is a concise, step by step, 'hands on' guide that describes both *
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32 * general multitasking concepts and FreeRTOS specifics. It presents and *
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33 * explains numerous examples that are written using the FreeRTOS API. *
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34 * Full source code for all the examples is provided in an accompanying *
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37 ***************************************************************************
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38 ***************************************************************************
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40 Please ensure to read the configuration and relevant port sections of the
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41 online documentation.
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43 http://www.FreeRTOS.org - Documentation, latest information, license and
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46 http://www.SafeRTOS.com - A version that is certified for use in safety
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49 http://www.OpenRTOS.com - Commercial support, development, porting,
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50 licensing and training services.
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54 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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56 *NOTE* - This file is designed to test some of the RTOS features - it is
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57 not intended to represent an efficient implementation!
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60 /* Standard includes. */
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63 /* Scheduler includes. */
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64 #include "FreeRTOS.h"
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67 /* Demo application includes. */
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71 /* Hardware specifics. */
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72 #define serRX_DATA_PIN ( 0x01 )
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73 #define serTX_DATA_PIN ( 0x02 )
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74 #define serCLOCK_Fxx_DIV_8 0x03
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75 #define serUPWR ( 0x80 )
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76 #define serUTXE ( 0x40 )
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77 #define serURXE ( 0x20 )
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78 #define serUCL ( 0x02 )
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79 #define serLSB ( 0x10 )
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82 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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83 #define serHANDLE ( ( xComPortHandle ) 1 )
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84 #define serNO_BLOCK ( ( portTickType ) 0 )
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86 /*-----------------------------------------------------------*/
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88 /* Queues used to hold received characters, and characters waiting to be
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90 static xQueueHandle xRxedChars;
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91 static xQueueHandle xCharsForTx;
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93 /*-----------------------------------------------------------*/
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95 /* Interrupt entry point written in the assembler file serialISR.s85. */
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96 extern void vSerialISREntry( void );
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98 /* Flag to indicate whether or not there are characters already queued to send. */
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99 static volatile unsigned long ulTxInProgress = pdFALSE;
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101 /*-----------------------------------------------------------*/
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104 * See the serial2.h header file.
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106 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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108 xComPortHandle xReturn = serHANDLE;
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109 const unsigned portLONG ulFuclk = ( configCPU_CLOCK_HZ / 2 ) / 8UL;
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111 /* Create the queues used to hold Rx and Tx characters. */
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112 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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113 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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115 /* If the queues were created correctly then setup the serial port
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117 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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119 portENTER_CRITICAL();
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121 /* Set the UART0 Rx and Tx pins to their alternative function. */
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122 PMC3 |= ( serRX_DATA_PIN | serTX_DATA_PIN );
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123 PM3 &= ~( serTX_DATA_PIN );
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125 /* Setup clock for required baud. */
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126 UD0CTL1 = serCLOCK_Fxx_DIV_8;
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127 UD0CTL2 = ulFuclk / ( 2 * ulWantedBaud );
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129 /* Enable, n81. */
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130 UD0CTL0 = ( serUPWR | serUTXE | serURXE | serUCL | serLSB );
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132 /* Enable interrupts for both Rx and Tx. */
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136 ulTxInProgress = pdFALSE;
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138 portEXIT_CRITICAL();
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142 xReturn = ( xComPortHandle ) 0;
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145 /* This demo file only supports a single port but we have to return
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146 something to comply with the standard demo header file. */
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149 /*-----------------------------------------------------------*/
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151 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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153 /* The port handle is not required as this driver only supports one port. */
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156 /* Get the next character from the buffer. Return false if no characters
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157 are available, or arrive before xBlockTime expires. */
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158 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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167 /*-----------------------------------------------------------*/
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169 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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171 signed portCHAR *pxNext;
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173 /* A couple of parameters that this port does not use. */
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174 ( void ) usStringLength;
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177 /* NOTE: This implementation does not handle the queue being full as no
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178 block time is used! */
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180 /* The port handle is not required as this driver only supports UART0. */
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183 /* Send each character in the string, one at a time. */
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184 pxNext = ( signed portCHAR * ) pcString;
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187 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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191 /*-----------------------------------------------------------*/
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193 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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195 portBASE_TYPE xReturn = pdPASS;
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197 portENTER_CRITICAL();
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199 /* There are currently no characters queued up to send so write the
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200 character directly to the UART. */
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201 if( ulTxInProgress == pdFALSE )
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204 ulTxInProgress = pdTRUE;
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208 /* The UART is already busy so write the character to the Tx queue.
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209 The queue is drained from within the Tx interrupt. */
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210 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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216 portEXIT_CRITICAL();
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220 /*-----------------------------------------------------------*/
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222 void vSerialClose( xComPortHandle xPort )
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224 /* Not supported as not required by the demo application. */
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226 /*-----------------------------------------------------------*/
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228 /* Tx interrupt handler. This is called from the asm file wrapper. */
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229 void vUARTTxISRHandler( void )
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232 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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234 /* Are there any more characters queue to transmit? */
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235 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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237 /* Send the next character. */
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242 /* The UART is no longer active. */
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243 ulTxInProgress = pdFALSE;
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246 /* If reading a character from the Rx queue caused a task to unblock, and
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247 the unblocked task has a priority higher than the currently running task,
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248 then xHigherPriorityTaskWoken will have been set to true and a context
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249 switch should occur now. */
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250 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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252 /*-----------------------------------------------------------*/
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254 /* Rx interrupt handler. This is called from the asm file wrapper. */
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255 void vUARTRxISRHandler( void )
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258 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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260 /* Send the received character to the Rx queue. */
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262 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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264 /* If sending a character to the Tx queue caused a task to unblock, and
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265 the unblocked task has a priority higher than the currently running task,
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266 then xHigherPriorityTaskWoken will have been set to true and a context
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267 switch should occur now. */
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268 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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