2 FreeRTOS V7.0.0 - Copyright (C) 2011 Real Time Engineers Ltd.
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5 ***************************************************************************
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7 * FreeRTOS tutorial books are available in pdf and paperback. *
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8 * Complete, revised, and edited pdf reference manuals are also *
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11 * Purchasing FreeRTOS documentation will not only help you, by *
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12 * ensuring you get running as quickly as possible and with an *
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13 * in-depth knowledge of how to use FreeRTOS, it will also help *
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14 * the FreeRTOS project to continue with its mission of providing *
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15 * professional grade, cross platform, de facto standard solutions *
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16 * for microcontrollers - completely free of charge! *
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18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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20 * Thank you for using FreeRTOS, and thank you for your support! *
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22 ***************************************************************************
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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 modification to the GPL is included to allow you to
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31 distribute a combined work that includes FreeRTOS without being obliged to
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32 provide the source code for proprietary components outside of the FreeRTOS
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33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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35 or 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 FOR UART0.
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57 *NOTE* - This file is designed to test some of the RTOS features - it is
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58 not intended to represent an efficient implementation!
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61 /* Standard includes. */
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64 /* Scheduler includes. */
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65 #include "FreeRTOS.h"
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68 /* Demo application includes. */
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72 /* Hardware specifics. */
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73 #define serRX_DATA_PIN ( 0x01 )
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74 #define serTX_DATA_PIN ( 0x02 )
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75 #define serCLOCK_Fxx_DIV_8 0x03
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76 #define serUPWR ( 0x80 )
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77 #define serUTXE ( 0x40 )
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78 #define serURXE ( 0x20 )
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79 #define serUCL ( 0x02 )
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80 #define serLSB ( 0x10 )
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83 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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84 #define serHANDLE ( ( xComPortHandle ) 1 )
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85 #define serNO_BLOCK ( ( portTickType ) 0 )
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87 /*-----------------------------------------------------------*/
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89 /* Queues used to hold received characters, and characters waiting to be
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91 static xQueueHandle xRxedChars;
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92 static xQueueHandle xCharsForTx;
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94 /*-----------------------------------------------------------*/
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96 /* Interrupt entry point written in the assembler file serialISR.s85. */
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97 extern void vSerialISREntry( void );
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99 /* Flag to indicate whether or not there are characters already queued to send. */
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100 static volatile unsigned long ulTxInProgress = pdFALSE;
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102 /*-----------------------------------------------------------*/
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105 * See the serial2.h header file.
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107 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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109 xComPortHandle xReturn = serHANDLE;
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110 const unsigned portLONG ulFuclk = ( configCPU_CLOCK_HZ / 2 ) / 8UL;
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112 /* Create the queues used to hold Rx and Tx characters. */
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113 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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114 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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116 /* If the queues were created correctly then setup the serial port
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118 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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120 portENTER_CRITICAL();
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122 /* Set the UART0 Rx and Tx pins to their alternative function. */
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123 PMC3 |= ( serRX_DATA_PIN | serTX_DATA_PIN );
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124 PM3 &= ~( serTX_DATA_PIN );
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126 /* Setup clock for required baud. */
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127 UD0CTL1 = serCLOCK_Fxx_DIV_8;
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128 UD0CTL2 = ulFuclk / ( 2 * ulWantedBaud );
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130 /* Enable, n81. */
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131 UD0CTL0 = ( serUPWR | serUTXE | serURXE | serUCL | serLSB );
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133 /* Enable interrupts for both Rx and Tx. */
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137 ulTxInProgress = pdFALSE;
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139 portEXIT_CRITICAL();
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143 xReturn = ( xComPortHandle ) 0;
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146 /* This demo file only supports a single port but we have to return
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147 something to comply with the standard demo header file. */
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150 /*-----------------------------------------------------------*/
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152 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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154 /* The port handle is not required as this driver only supports one port. */
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157 /* Get the next character from the buffer. Return false if no characters
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158 are available, or arrive before xBlockTime expires. */
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159 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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168 /*-----------------------------------------------------------*/
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170 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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172 signed portCHAR *pxNext;
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174 /* A couple of parameters that this port does not use. */
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175 ( void ) usStringLength;
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178 /* NOTE: This implementation does not handle the queue being full as no
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179 block time is used! */
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181 /* The port handle is not required as this driver only supports UART0. */
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184 /* Send each character in the string, one at a time. */
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185 pxNext = ( signed portCHAR * ) pcString;
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188 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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192 /*-----------------------------------------------------------*/
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194 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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196 portBASE_TYPE xReturn = pdPASS;
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198 portENTER_CRITICAL();
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200 /* There are currently no characters queued up to send so write the
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201 character directly to the UART. */
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202 if( ulTxInProgress == pdFALSE )
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205 ulTxInProgress = pdTRUE;
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209 /* The UART is already busy so write the character to the Tx queue.
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210 The queue is drained from within the Tx interrupt. */
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211 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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217 portEXIT_CRITICAL();
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221 /*-----------------------------------------------------------*/
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223 void vSerialClose( xComPortHandle xPort )
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225 /* Not supported as not required by the demo application. */
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227 /*-----------------------------------------------------------*/
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229 /* Tx interrupt handler. This is called from the asm file wrapper. */
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230 void vUARTTxISRHandler( void )
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233 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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235 /* Are there any more characters queue to transmit? */
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236 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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238 /* Send the next character. */
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243 /* The UART is no longer active. */
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244 ulTxInProgress = pdFALSE;
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247 /* If reading a character from the Rx queue caused a task to unblock, and
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248 the unblocked task has a priority higher than the currently running task,
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249 then xHigherPriorityTaskWoken will have been set to true and a context
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250 switch should occur now. */
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251 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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253 /*-----------------------------------------------------------*/
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255 /* Rx interrupt handler. This is called from the asm file wrapper. */
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256 void vUARTRxISRHandler( void )
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259 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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261 /* Send the received character to the Rx queue. */
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263 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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265 /* If sending a character to the Tx queue caused a task to unblock, and
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266 the unblocked task has a priority higher than the currently running task,
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267 then xHigherPriorityTaskWoken will have been set to true and a context
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268 switch should occur now. */
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269 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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