2 FreeRTOS V7.2.0 - Copyright (C) 2012 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 ***************************************************************************
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46 * Having a problem? Start by reading the FAQ "My application does *
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47 * not run, what could be wrong? *
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49 * http://www.FreeRTOS.org/FAQHelp.html *
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51 ***************************************************************************
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54 http://www.FreeRTOS.org - Documentation, training, latest information,
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55 license and contact details.
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57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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58 including FreeRTOS+Trace - an indispensable productivity tool.
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60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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61 the code with commercial support, indemnification, and middleware, under
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62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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63 provide a safety engineered and independently SIL3 certified version under
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64 the SafeRTOS brand: http://www.SafeRTOS.com.
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67 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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69 * This file only supports UART 0
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72 /* Standard includes. */
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75 /* Scheduler includes. */
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76 #include "FreeRTOS.h"
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80 /* Demo application includes. */
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83 /* The queue used to hold received characters. */
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84 static xQueueHandle xRxedChars;
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86 /* The queue used to hold characters waiting transmission. */
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87 static xQueueHandle xCharsForTx;
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89 static volatile portSHORT sTHREEmpty;
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91 static volatile portSHORT queueFail = pdFALSE;
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93 /*-----------------------------------------------------------*/
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94 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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96 /* Initialise the hardware. */
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97 portENTER_CRITICAL();
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99 /* Create the queues used by the com test task. */
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100 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) );
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101 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) );
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103 if( xRxedChars == 0 )
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105 queueFail = pdTRUE;
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108 if( xCharsForTx == 0 )
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110 queueFail = pdTRUE;
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113 /* Initialize UART asynchronous mode */
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114 BGR0 = configCLKP1_CLOCK_HZ / ulWantedBaud;
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116 SCR0 = 0x17; /* 8N1 */
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117 SMR0 = 0x0d; /* enable SOT3, Reset, normal mode */
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118 SSR0 = 0x02; /* LSB first, enable receive interrupts */
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120 PIER08_IE2 = 1; /* enable input */
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121 DDR08_D2 = 0; /* switch P08_2 to input */
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122 DDR08_D3 = 1; /* switch P08_3 to output */
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124 portEXIT_CRITICAL();
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126 /* Unlike other ports, this serial code does not allow for more than one
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127 com port. We therefore don't return a pointer to a port structure and can
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128 instead just return NULL. */
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131 /*-----------------------------------------------------------*/
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133 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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135 /* Get the next character from the buffer. Return false if no characters
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136 are available, or arrive before xBlockTime expires. */
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137 if( xQueueReceive(xRxedChars, pcRxedChar, xBlockTime) )
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146 /*-----------------------------------------------------------*/
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148 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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150 signed portBASE_TYPE xReturn;
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152 /* Transmit a character. */
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153 portENTER_CRITICAL();
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155 if( sTHREEmpty == pdTRUE )
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157 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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158 there are no characters queued to be transmitted - so we can
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159 write the character directly to the shift Tx register. */
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160 sTHREEmpty = pdFALSE;
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166 /* sTHREEmpty is false, so there are still characters waiting to be
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167 transmitted. We have to queue this character so it gets
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168 transmitted in turn. */
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170 /* Return false if after the block time there is no room on the Tx
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171 queue. It is ok to block inside a critical section as each task
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172 maintains it's own critical section status. */
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173 if( xQueueSend(xCharsForTx, &cOutChar, xBlockTime) == pdTRUE )
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183 if( pdPASS == xReturn )
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185 /* Turn on the Tx interrupt so the ISR will remove the character from the
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186 queue and send it. This does not need to be in a critical section as
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187 if the interrupt has already removed the character the next interrupt
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188 will simply turn off the Tx interrupt again. */
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192 portEXIT_CRITICAL();
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196 /*-----------------------------------------------------------*/
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199 * UART RX interrupt service routine.
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201 __interrupt void UART0_RxISR( void )
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203 volatile signed portCHAR cChar;
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204 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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206 /* Get the character from the UART and post it on the queue of Rxed
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210 xQueueSendFromISR( xRxedChars, ( const void *const ) &cChar, &xHigherPriorityTaskWoken );
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212 if( xHigherPriorityTaskWoken )
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214 /*If the post causes a task to wake force a context switch
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215 as the woken task may have a higher priority than the task we have
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217 portYIELD_FROM_ISR();
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220 /*-----------------------------------------------------------*/
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223 * UART Tx interrupt service routine.
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225 __interrupt void UART0_TxISR( void )
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227 signed portCHAR cChar;
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228 signed portBASE_TYPE xTaskWoken = pdFALSE;
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230 /* The previous character has been transmitted. See if there are any
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231 further characters waiting transmission. */
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232 if( xQueueReceiveFromISR(xCharsForTx, &cChar, &xTaskWoken) == pdTRUE )
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234 /* There was another character queued - transmit it now. */
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239 /* There were no other characters to transmit. */
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240 sTHREEmpty = pdTRUE;
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242 /* Disable transmit interrupts */
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