2 FreeRTOS V7.4.0 - Copyright (C) 2013 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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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not itcan be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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75 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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77 * This file only supports UART 0
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80 /* Standard includes. */
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83 /* Scheduler includes. */
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84 #include "FreeRTOS.h"
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88 /* Demo application includes. */
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91 /* The queue used to hold received characters. */
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92 static xQueueHandle xRxedChars;
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94 /* The queue used to hold characters waiting transmission. */
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95 static xQueueHandle xCharsForTx;
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97 static volatile portSHORT sTHREEmpty;
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99 static volatile portSHORT queueFail = pdFALSE;
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101 /*-----------------------------------------------------------*/
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102 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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104 /* Initialise the hardware. */
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105 portENTER_CRITICAL();
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107 /* Create the queues used by the com test task. */
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108 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) );
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109 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof(signed portCHAR) );
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111 if( xRxedChars == 0 )
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113 queueFail = pdTRUE;
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116 if( xCharsForTx == 0 )
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118 queueFail = pdTRUE;
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121 /* Initialize UART asynchronous mode */
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122 BGR0 = configCLKP1_CLOCK_HZ / ulWantedBaud;
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124 SCR0 = 0x17; /* 8N1 */
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125 SMR0 = 0x0d; /* enable SOT3, Reset, normal mode */
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126 SSR0 = 0x02; /* LSB first, enable receive interrupts */
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128 PIER08_IE2 = 1; /* enable input */
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129 DDR08_D2 = 0; /* switch P08_2 to input */
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130 DDR08_D3 = 1; /* switch P08_3 to output */
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132 portEXIT_CRITICAL();
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134 /* Unlike other ports, this serial code does not allow for more than one
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135 com port. We therefore don't return a pointer to a port structure and can
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136 instead just return NULL. */
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139 /*-----------------------------------------------------------*/
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141 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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143 /* Get the next character from the buffer. Return false if no characters
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144 are available, or arrive before xBlockTime expires. */
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145 if( xQueueReceive(xRxedChars, pcRxedChar, xBlockTime) )
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154 /*-----------------------------------------------------------*/
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156 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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158 signed portBASE_TYPE xReturn;
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160 /* Transmit a character. */
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161 portENTER_CRITICAL();
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163 if( sTHREEmpty == pdTRUE )
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165 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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166 there are no characters queued to be transmitted - so we can
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167 write the character directly to the shift Tx register. */
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168 sTHREEmpty = pdFALSE;
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174 /* sTHREEmpty is false, so there are still characters waiting to be
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175 transmitted. We have to queue this character so it gets
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176 transmitted in turn. */
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178 /* Return false if after the block time there is no room on the Tx
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179 queue. It is ok to block inside a critical section as each task
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180 maintains it's own critical section status. */
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181 if( xQueueSend(xCharsForTx, &cOutChar, xBlockTime) == pdTRUE )
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191 if( pdPASS == xReturn )
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193 /* Turn on the Tx interrupt so the ISR will remove the character from the
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194 queue and send it. This does not need to be in a critical section as
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195 if the interrupt has already removed the character the next interrupt
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196 will simply turn off the Tx interrupt again. */
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200 portEXIT_CRITICAL();
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204 /*-----------------------------------------------------------*/
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207 * UART RX interrupt service routine.
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209 __interrupt void UART0_RxISR( void )
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211 volatile signed portCHAR cChar;
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212 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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214 /* Get the character from the UART and post it on the queue of Rxed
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218 xQueueSendFromISR( xRxedChars, ( const void *const ) &cChar, &xHigherPriorityTaskWoken );
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220 if( xHigherPriorityTaskWoken )
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222 /*If the post causes a task to wake force a context switch
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223 as the woken task may have a higher priority than the task we have
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225 portYIELD_FROM_ISR();
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228 /*-----------------------------------------------------------*/
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231 * UART Tx interrupt service routine.
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233 __interrupt void UART0_TxISR( void )
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235 signed portCHAR cChar;
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236 signed portBASE_TYPE xTaskWoken = pdFALSE;
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238 /* The previous character has been transmitted. See if there are any
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239 further characters waiting transmission. */
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240 if( xQueueReceiveFromISR(xCharsForTx, &cChar, &xTaskWoken) == pdTRUE )
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242 /* There was another character queued - transmit it now. */
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247 /* There were no other characters to transmit. */
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248 sTHREEmpty = pdTRUE;
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250 /* Disable transmit interrupts */
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