2 FreeRTOS.org V5.2.0 - 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 it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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15 You should have received a copy of the GNU General Public License along
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16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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19 A special exception to the GPL is included to allow you to distribute a
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20 combined work that includes FreeRTOS.org without being obliged to provide
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21 the source code for any proprietary components. See the licensing section
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22 of http://www.FreeRTOS.org for full details.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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53 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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55 *NOTE* - This file is designed to test some of the RTOS features - it is
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56 not intended to represent an efficient implementation!
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59 /* Standard includes. */
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62 /* Scheduler includes. */
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63 #include "FreeRTOS.h"
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66 /* Demo application includes. */
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70 /* Hardware specifics. */
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71 #define serRX_DATA_PIN ( 0x01 )
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72 #define serTX_DATA_PIN ( 0x02 )
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73 #define serCLOCK_Fxx_DIV_8 0x03
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74 #define serUPWR ( 0x80 )
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75 #define serUTXE ( 0x40 )
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76 #define serURXE ( 0x20 )
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77 #define serUCL ( 0x02 )
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78 #define serLSB ( 0x10 )
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81 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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82 #define serHANDLE ( ( xComPortHandle ) 1 )
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83 #define serNO_BLOCK ( ( portTickType ) 0 )
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85 /*-----------------------------------------------------------*/
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87 /* Queues used to hold received characters, and characters waiting to be
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89 static xQueueHandle xRxedChars;
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90 static xQueueHandle xCharsForTx;
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92 /*-----------------------------------------------------------*/
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94 /* Interrupt entry point written in the assembler file serialISR.s85. */
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95 extern void vSerialISREntry( void );
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97 /* Flag to indicate whether or not there are characters already queued to send. */
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98 static volatile unsigned long ulTxInProgress = pdFALSE;
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100 /*-----------------------------------------------------------*/
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103 * See the serial2.h header file.
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105 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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107 xComPortHandle xReturn = serHANDLE;
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108 const unsigned portLONG ulFuclk = ( configCPU_CLOCK_HZ / 2 ) / 8UL;
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110 /* Create the queues used to hold Rx and Tx characters. */
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111 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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112 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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114 /* If the queues were created correctly then setup the serial port
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116 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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118 portENTER_CRITICAL();
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120 /* Set the UART0 Rx and Tx pins to their alternative function. */
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121 PMC3 |= ( serRX_DATA_PIN | serTX_DATA_PIN );
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122 PM3 &= ~( serTX_DATA_PIN );
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124 /* Setup clock for required baud. */
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125 UD0CTL1 = serCLOCK_Fxx_DIV_8;
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126 UD0CTL2 = ulFuclk / ( 2 * ulWantedBaud );
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128 /* Enable, n81. */
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129 UD0CTL0 = ( serUPWR | serUTXE | serURXE | serUCL | serLSB );
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131 /* Enable interrupts for both Rx and Tx. */
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135 ulTxInProgress = pdFALSE;
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137 portEXIT_CRITICAL();
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141 xReturn = ( xComPortHandle ) 0;
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144 /* This demo file only supports a single port but we have to return
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145 something to comply with the standard demo header file. */
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148 /*-----------------------------------------------------------*/
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150 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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152 /* The port handle is not required as this driver only supports one port. */
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155 /* Get the next character from the buffer. Return false if no characters
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156 are available, or arrive before xBlockTime expires. */
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157 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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166 /*-----------------------------------------------------------*/
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168 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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170 signed portCHAR *pxNext;
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172 /* A couple of parameters that this port does not use. */
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173 ( void ) usStringLength;
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176 /* NOTE: This implementation does not handle the queue being full as no
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177 block time is used! */
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179 /* The port handle is not required as this driver only supports UART0. */
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182 /* Send each character in the string, one at a time. */
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183 pxNext = ( signed portCHAR * ) pcString;
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186 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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190 /*-----------------------------------------------------------*/
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192 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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194 portBASE_TYPE xReturn = pdPASS;
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196 portENTER_CRITICAL();
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198 /* There are currently no characters queued up to send so write the
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199 character directly to the UART. */
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200 if( ulTxInProgress == pdFALSE )
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203 ulTxInProgress = pdTRUE;
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207 /* The UART is already busy so write the character to the Tx queue.
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208 The queue is drained from within the Tx interrupt. */
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209 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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215 portEXIT_CRITICAL();
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219 /*-----------------------------------------------------------*/
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221 void vSerialClose( xComPortHandle xPort )
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223 /* Not supported as not required by the demo application. */
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225 /*-----------------------------------------------------------*/
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227 /* Tx interrupt handler. This is called from the asm file wrapper. */
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228 void vUARTTxISRHandler( void )
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231 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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233 /* Are there any more characters queue to transmit? */
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234 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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236 /* Send the next character. */
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241 /* The UART is no longer active. */
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242 ulTxInProgress = pdFALSE;
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245 /* If reading a character from the Rx queue caused a task to unblock, and
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246 the unblocked task has a priority higher than the currently running task,
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247 then xHigherPriorityTaskWoken will have been set to true and a context
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248 switch should occur now. */
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249 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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251 /*-----------------------------------------------------------*/
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253 /* Rx interrupt handler. This is called from the asm file wrapper. */
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254 void vUARTRxISRHandler( void )
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257 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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259 /* Send the received character to the Rx queue. */
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261 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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263 /* If sending a character to the Tx queue caused a task to unblock, and
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264 the unblocked task has a priority higher than the currently running task,
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265 then xHigherPriorityTaskWoken will have been set to true and a context
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266 switch should occur now. */
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267 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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