2 FreeRTOS V7.4.1 - 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 it can 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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78 + The function xPortInitMinimal() has been renamed to
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79 xSerialPortInitMinimal() and the function xPortInit() has been renamed
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80 to xSerialPortInit().
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84 + Delay periods are now specified using variables and constants of
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85 portTickType rather than unsigned long.
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86 + xQueueReceiveFromISR() used in place of xQueueReceive() within the ISR.
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90 + Replaced the inb() and outb() functions with direct memory
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91 access. This allows the port to be built with the 20050414 build of
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95 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER. */
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99 #include <avr/interrupt.h>
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100 #include "FreeRTOS.h"
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103 #include "serial.h"
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105 #define serBAUD_DIV_CONSTANT ( ( unsigned long ) 16 )
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107 /* Constants for writing to UCSRB. */
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108 #define serRX_INT_ENABLE ( ( unsigned char ) 0x80 )
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109 #define serRX_ENABLE ( ( unsigned char ) 0x10 )
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110 #define serTX_ENABLE ( ( unsigned char ) 0x08 )
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111 #define serTX_INT_ENABLE ( ( unsigned char ) 0x20 )
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113 /* Constants for writing to UCSRC. */
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114 #define serUCSRC_SELECT ( ( unsigned char ) 0x80 )
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115 #define serEIGHT_DATA_BITS ( ( unsigned char ) 0x06 )
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117 static xQueueHandle xRxedChars;
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118 static xQueueHandle xCharsForTx;
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120 #define vInterruptOn() \
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122 unsigned char ucByte; \
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125 ucByte |= serTX_INT_ENABLE; \
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128 /*-----------------------------------------------------------*/
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130 #define vInterruptOff() \
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132 unsigned char ucInByte; \
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134 ucInByte = UCSRB; \
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135 ucInByte &= ~serTX_INT_ENABLE; \
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136 UCSRB = ucInByte; \
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138 /*-----------------------------------------------------------*/
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140 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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142 unsigned long ulBaudRateCounter;
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143 unsigned char ucByte;
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145 portENTER_CRITICAL();
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147 /* Create the queues used by the com test task. */
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148 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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149 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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151 /* Calculate the baud rate register value from the equation in the
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153 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned long ) 1;
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155 /* Set the baud rate. */
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156 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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159 ulBaudRateCounter >>= ( unsigned long ) 8;
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160 ucByte = ( unsigned char ) ( ulBaudRateCounter & ( unsigned long ) 0xff );
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163 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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164 later. Also enable the Rx and Tx. */
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165 UCSRB = ( serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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167 /* Set the data bits to 8. */
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168 UCSRC = ( serUCSRC_SELECT | serEIGHT_DATA_BITS );
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170 portEXIT_CRITICAL();
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172 /* Unlike other ports, this serial code does not allow for more than one
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173 com port. We therefore don't return a pointer to a port structure and can
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174 instead just return NULL. */
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177 /*-----------------------------------------------------------*/
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179 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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181 /* Only one port is supported. */
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184 /* Get the next character from the buffer. Return false if no characters
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185 are available, or arrive before xBlockTime expires. */
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186 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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195 /*-----------------------------------------------------------*/
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197 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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199 /* Only one port is supported. */
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202 /* Return false if after the block time there is no room on the Tx queue. */
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203 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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212 /*-----------------------------------------------------------*/
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214 void vSerialClose( xComPortHandle xPort )
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216 unsigned char ucByte;
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218 /* The parameter is not used. */
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221 /* Turn off the interrupts. We may also want to delete the queues and/or
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222 re-install the original ISR. */
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224 portENTER_CRITICAL();
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228 ucByte &= ~serRX_INT_ENABLE;
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231 portEXIT_CRITICAL();
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233 /*-----------------------------------------------------------*/
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235 SIGNAL( SIG_UART_RECV )
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238 signed portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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240 /* Get the character and post it on the queue of Rxed characters.
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241 If the post causes a task to wake force a context switch as the woken task
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242 may have a higher priority than the task we have interrupted. */
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245 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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247 if( xHigherPriorityTaskWoken != pdFALSE )
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252 /*-----------------------------------------------------------*/
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254 SIGNAL( SIG_UART_DATA )
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256 signed char cChar, cTaskWoken;
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258 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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260 /* Send the next character queued for Tx. */
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265 /* Queue empty, nothing to send. */
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