2 FreeRTOS.org V5.2.0 - Copyright (C) 2003-2009 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify it
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7 under the terms of the GNU General Public License (version 2) as published
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8 by the Free Software Foundation and modified by the FreeRTOS exception.
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10 FreeRTOS.org is distributed in the hope that it will be useful, but WITHOUT
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11 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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15 You should have received a copy of the GNU General Public License along
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16 with FreeRTOS.org; if not, write to the Free Software Foundation, Inc., 59
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17 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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19 A special exception to the GPL is included to allow you to distribute a
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20 combined work that includes FreeRTOS.org without being obliged to provide
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21 the source code for any proprietary components. See the licensing section
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22 of http://www.FreeRTOS.org for full details.
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25 ***************************************************************************
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27 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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29 * This is a concise, step by step, 'hands on' guide that describes both *
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30 * general multitasking concepts and FreeRTOS specifics. It presents and *
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31 * explains numerous examples that are written using the FreeRTOS API. *
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32 * Full source code for all the examples is provided in an accompanying *
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35 ***************************************************************************
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39 Please ensure to read the configuration and relevant port sections of the
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40 online documentation.
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42 http://www.FreeRTOS.org - Documentation, latest information, license and
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45 http://www.SafeRTOS.com - A version that is certified for use in safety
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48 http://www.OpenRTOS.com - Commercial support, development, porting,
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49 licensing and training services.
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53 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR IAR AVR PORT. */
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57 #include "FreeRTOS.h"
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62 #define serBAUD_DIV_CONSTANT ( ( unsigned portLONG ) 16 )
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64 /* Constants for writing to UCSRB. */
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65 #define serRX_INT_ENABLE ( ( unsigned portCHAR ) 0x80 )
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66 #define serRX_ENABLE ( ( unsigned portCHAR ) 0x10 )
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67 #define serTX_ENABLE ( ( unsigned portCHAR ) 0x08 )
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68 #define serTX_INT_ENABLE ( ( unsigned portCHAR ) 0x20 )
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70 /* Constants for writing to UCSRC. */
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71 #define serUCSRC_SELECT ( ( unsigned portCHAR ) 0x80 )
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72 #define serEIGHT_DATA_BITS ( ( unsigned portCHAR ) 0x06 )
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74 static xQueueHandle xRxedChars;
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75 static xQueueHandle xCharsForTx;
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77 #define vInterruptOn() \
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79 unsigned portCHAR ucByte; \
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82 ucByte |= serTX_INT_ENABLE; \
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83 outb( UCSRB, ucByte ); \
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85 /*-----------------------------------------------------------*/
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87 #define vInterruptOff() \
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89 unsigned portCHAR ucByte; \
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92 ucByte &= ~serTX_INT_ENABLE; \
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93 outb( UCSRB, ucByte ); \
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95 /*-----------------------------------------------------------*/
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97 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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99 unsigned portLONG ulBaudRateCounter;
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100 unsigned portCHAR ucByte;
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102 portENTER_CRITICAL();
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104 /* Create the queues used by the com test task. */
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105 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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106 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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108 /* Calculate the baud rate register value from the equation in the
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110 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned portLONG ) 1;
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112 /* Set the baud rate. */
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113 ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
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114 outb( UBRRL, ucByte );
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116 ulBaudRateCounter >>= ( unsigned portLONG ) 8;
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117 ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );
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118 outb( UBRRH, ucByte );
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120 /* Enable the Rx interrupt. The Tx interrupt will get enabled
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121 later. Also enable the Rx and Tx. */
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122 outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );
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124 /* Set the data bits to 8. */
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125 outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS );
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127 portEXIT_CRITICAL();
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129 /* Unlike other ports, this serial code does not allow for more than one
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130 com port. We therefore don't return a pointer to a port structure and can
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131 instead just return NULL. */
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134 /*-----------------------------------------------------------*/
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136 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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138 /* Get the next character from the buffer. Return false if no characters
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139 are available, or arrive before xBlockTime expires. */
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140 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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149 /*-----------------------------------------------------------*/
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151 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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153 /* Return false if after the block time there is no room on the Tx queue. */
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154 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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163 /*-----------------------------------------------------------*/
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165 void vSerialClose( xComPortHandle xPort )
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167 unsigned portCHAR ucByte;
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169 /* Turn off the interrupts. We may also want to delete the queues and/or
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170 re-install the original ISR. */
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172 portENTER_CRITICAL();
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176 ucByte &= ~serRX_INT_ENABLE;
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177 outb( UCSRB, ucByte );
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179 portEXIT_CRITICAL();
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181 /*-----------------------------------------------------------*/
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183 __interrupt void SIG_UART_RECV( void )
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185 signed portCHAR ucChar, xHigherPriorityTaskWoken = pdFALSE;
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187 /* Get the character and post it on the queue of Rxed characters.
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188 If the post causes a task to wake force a context switch as the woken task
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189 may have a higher priority than the task we have interrupted. */
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192 xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
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194 if( xHigherPriorityTaskWoken != pdFALSE )
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199 /*-----------------------------------------------------------*/
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201 __interrupt void SIG_UART_DATA( void )
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203 signed portCHAR cChar, cTaskWoken = pdFALSE;
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205 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )
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207 /* Send the next character queued for Tx. */
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208 outb( UDR, cChar );
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212 /* Queue empty, nothing to send. */
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