2 FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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32 >>>NOTE<<< The modification to the GPL is included to allow you to
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33 distribute a combined work that includes FreeRTOS without being obliged to
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34 provide the source code for proprietary components outside of the FreeRTOS
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35 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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36 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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37 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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38 more details. You should have received a copy of the GNU General Public
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39 License and the FreeRTOS license exception along with FreeRTOS; if not it
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40 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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41 by writing to Richard Barry, contact details for whom are available on the
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46 ***************************************************************************
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48 * Having a problem? Start by reading the FAQ "My application does *
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49 * not run, what could be wrong?" *
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51 * http://www.FreeRTOS.org/FAQHelp.html *
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53 ***************************************************************************
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56 http://www.FreeRTOS.org - Documentation, training, latest versions, license
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57 and contact details.
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59 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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60 including FreeRTOS+Trace - an indispensable productivity tool.
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62 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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63 the code with commercial support, indemnification, and middleware, under
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64 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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65 provide a safety engineered and independently SIL3 certified version under
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66 the SafeRTOS brand: http://www.SafeRTOS.com.
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71 * BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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73 * This file only supports UART 2
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76 /* Standard includes. */
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79 /* Scheduler includes. */
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80 #include "FreeRTOS.h"
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84 /* Demo application includes. */
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87 /* The queue used to hold received characters. */
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88 static xQueueHandle xRxedChars;
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90 /* The queue used to hold characters waiting transmission. */
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91 static xQueueHandle xCharsForTx;
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93 static volatile portSHORT sTHREEmpty;
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95 /*-----------------------------------------------------------*/
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97 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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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 /* Initialize UART asynchronous mode */
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106 BGR02 = configPER_CLOCK_HZ / ulWantedBaud;
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108 SCR02 = 0x17; /* 8N1 */
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109 SMR02 = 0x0d; /* enable SOT3, Reset, normal mode */
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110 SSR02 = 0x02; /* LSB first, enable receive interrupts */
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112 PFR20_D0 = 1; /* enable UART */
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113 PFR20_D1 = 1; /* enable UART */
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115 EPFR20_D1 = 0; /* enable UART */
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117 portEXIT_CRITICAL();
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119 /* Unlike other ports, this serial code does not allow for more than one
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120 com port. We therefore don't return a pointer to a port structure and can
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121 instead just return NULL. */
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124 /*-----------------------------------------------------------*/
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126 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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128 /* Get the next character from the buffer. Return false if no characters
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129 are available, or arrive before xBlockTime expires. */
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130 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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139 /*-----------------------------------------------------------*/
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141 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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143 signed portBASE_TYPE xReturn;
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145 /* Transmit a character. */
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146 portENTER_CRITICAL();
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148 if( sTHREEmpty == pdTRUE )
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150 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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151 there are no characters queued to be transmitted - so we can
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152 write the character directly to the shift Tx register. */
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153 sTHREEmpty = pdFALSE;
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159 /* sTHREEmpty is false, so there are still characters waiting to be
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160 transmitted. We have to queue this character so it gets
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161 transmitted in turn. */
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163 /* Return false if after the block time there is no room on the Tx
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164 queue. It is ok to block inside a critical section as each task
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165 maintains it's own critical section status. */
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166 if (xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdTRUE)
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176 if (pdPASS == xReturn)
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178 /* Turn on the Tx interrupt so the ISR will remove the character from the
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179 queue and send it. This does not need to be in a critical section as
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180 if the interrupt has already removed the character the next interrupt
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181 will simply turn off the Tx interrupt again. */
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186 portEXIT_CRITICAL();
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190 /*-----------------------------------------------------------*/
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193 * UART RX interrupt service routine.
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195 __interrupt void UART2_RxISR (void)
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197 signed portCHAR cChar;
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198 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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200 /* Get the character from the UART and post it on the queue of Rxed
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204 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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206 if( xHigherPriorityTaskWoken )
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208 /*If the post causes a task to wake force a context switch
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209 as the woken task may have a higher priority than the task we have
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211 portYIELD_FROM_ISR();
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215 /*-----------------------------------------------------------*/
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218 * UART Tx interrupt service routine.
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220 __interrupt void UART2_TxISR (void)
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222 signed portCHAR cChar;
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223 signed portBASE_TYPE xTaskWoken = pdFALSE;
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225 /* The previous character has been transmitted. See if there are any
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226 further characters waiting transmission. */
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227 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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229 /* There was another character queued - transmit it now. */
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234 /* There were no other characters to transmit. */
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235 sTHREEmpty = pdTRUE;
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237 /* Disable transmit interrupts */
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