2 FreeRTOS V7.5.2 - Copyright (C) 2013 Real Time Engineers Ltd.
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4 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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6 ***************************************************************************
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8 * FreeRTOS provides completely free yet professionally developed, *
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9 * robust, strictly quality controlled, supported, and cross *
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10 * platform software that has become a de facto standard. *
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12 * Help yourself get started quickly and support the FreeRTOS *
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13 * project by purchasing a FreeRTOS tutorial book, reference *
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14 * manual, or both from: http://www.FreeRTOS.org/Documentation *
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18 ***************************************************************************
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20 This file is part of the FreeRTOS distribution.
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22 FreeRTOS is free software; you can redistribute it and/or modify it under
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23 the terms of the GNU General Public License (version 2) as published by the
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24 Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.
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26 >>! NOTE: The modification to the GPL is included to allow you to distribute
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27 >>! a combined work that includes FreeRTOS without being obliged to provide
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28 >>! the source code for proprietary components outside of the FreeRTOS
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31 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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32 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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33 FOR A PARTICULAR PURPOSE. Full license text is available from the following
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34 link: http://www.freertos.org/a00114.html
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38 ***************************************************************************
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40 * Having a problem? Start by reading the FAQ "My application does *
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41 * not run, what could be wrong?" *
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43 * http://www.FreeRTOS.org/FAQHelp.html *
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45 ***************************************************************************
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47 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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48 license and Real Time Engineers Ltd. contact details.
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50 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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51 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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52 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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54 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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55 Integrity Systems to sell under the OpenRTOS brand. Low cost OpenRTOS
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56 licenses offer ticketed support, indemnification and middleware.
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58 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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59 engineered and independently SIL3 certified version for use in safety and
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60 mission critical applications that require provable dependability.
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66 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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69 /* Standard includes. */
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72 /* Scheduler includes. */
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73 #include "FreeRTOS.h"
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76 /* Demo application includes. */
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79 /* Atmel library includes. */
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80 #include <usart/usart.h>
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81 #include <aic/aic.h>
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82 #include <pmc/pmc.h>
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84 /*-----------------------------------------------------------*/
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86 /* Location of the COM0 registers. */
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87 #define serCOM0 ( ( AT91PS_USART ) AT91C_BASE_US0 )
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89 /* Interrupt control macros. */
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90 #define serINTERRUPT_LEVEL ( 5 )
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91 #define vInterruptOn() serCOM0->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY )
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92 #define vInterruptOff() serCOM0->US_IDR = AT91C_US_TXRDY
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94 /* Misc constants. */
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95 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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96 #define serHANDLE ( ( xComPortHandle ) 1 )
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97 #define serNO_BLOCK ( ( portTickType ) 0 )
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98 #define serNO_TIMEGUARD ( ( unsigned long ) 0 )
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99 #define serNO_PERIPHERAL_B_SETUP ( ( unsigned long ) 0 )
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102 /* Queues used to hold received characters, and characters waiting to be
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104 static xQueueHandle xRxedChars;
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105 static xQueueHandle xCharsForTx;
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107 /*-----------------------------------------------------------*/
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109 /* The interrupt service routine. */
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110 __arm void vSerialISR( void );
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112 /*-----------------------------------------------------------*/
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115 * See the serial2.h header file.
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117 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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119 xComPortHandle xReturn = serHANDLE;
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121 /* Create the queues used to hold Rx and Tx characters. */
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122 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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123 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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125 /* If the queues were created correctly then setup the serial port
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127 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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129 PMC_EnablePeripheral( AT91C_ID_US0 );
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130 portENTER_CRITICAL();
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132 USART_Configure( serCOM0, ( AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE ), ulWantedBaud, configCPU_CLOCK_HZ );
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134 /* Enable Rx and Tx. */
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135 USART_SetTransmitterEnabled( serCOM0, pdTRUE );
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136 USART_SetReceiverEnabled( serCOM0, pdTRUE );
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138 /* Enable the Rx interrupts. The Tx interrupts are not enabled
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139 until there are characters to be transmitted. */
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140 serCOM0->US_IER = AT91C_US_RXRDY;
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142 /* Enable the interrupts in the AIC. */
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143 AIC_ConfigureIT( AT91C_ID_US0, AT91C_AIC_PRIOR_LOWEST, ( void (*)( void ) ) vSerialISR );
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144 AIC_EnableIT( AT91C_ID_US0 );
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146 portEXIT_CRITICAL();
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150 xReturn = ( xComPortHandle ) 0;
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153 /* This demo file only supports a single port but we have to return
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154 something to comply with the standard demo header file. */
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157 /*-----------------------------------------------------------*/
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159 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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161 /* The port handle is not required as this driver only supports one port. */
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164 /* Get the next character from the buffer. Return false if no characters
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165 are available, or arrive before xBlockTime expires. */
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166 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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175 /*-----------------------------------------------------------*/
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177 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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179 signed char *pxNext;
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181 /* A couple of parameters that this port does not use. */
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182 ( void ) usStringLength;
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185 /* NOTE: This implementation does not handle the queue being full as no
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186 block time is used! */
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188 /* The port handle is not required as this driver only supports UART0. */
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191 /* Send each character in the string, one at a time. */
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192 pxNext = ( signed char * ) pcString;
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195 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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199 /*-----------------------------------------------------------*/
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201 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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203 /* Just to remove compiler warning. */
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206 /* Place the character in the queue of characters to be transmitted. */
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207 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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212 /* Turn on the Tx interrupt so the ISR will remove the character from the
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213 queue and send it. This does not need to be in a critical section as
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214 if the interrupt has already removed the character the next interrupt
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215 will simply turn off the Tx interrupt again. */
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220 /*-----------------------------------------------------------*/
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222 void vSerialClose( xComPortHandle xPort )
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224 /* Not supported as not required by the demo application. */
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227 /*-----------------------------------------------------------*/
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229 /* Serial port ISR. This can cause a context switch so is not defined as a
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230 standard ISR using the __irq keyword. Instead a wrapper function is defined
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231 within serialISR.s79 which in turn calls this function. See the port
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232 documentation on the FreeRTOS.org website for more information. */
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233 __arm void vSerialISR( void )
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235 unsigned long ulStatus;
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237 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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239 /* What caused the interrupt? */
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240 ulStatus = serCOM0->US_CSR &= serCOM0->US_IMR;
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242 if( ulStatus & AT91C_US_TXRDY )
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244 /* The interrupt was caused by the THR becoming empty. Are there any
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245 more characters to transmit? */
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246 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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248 /* A character was retrieved from the queue so can be sent to the
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250 serCOM0->US_THR = cChar;
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254 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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259 if( ulStatus & AT91C_US_RXRDY )
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261 /* The interrupt was caused by a character being received. Grab the
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262 character from the RHR and place it in the queue or received
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264 cChar = serCOM0->US_RHR;
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265 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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268 /* If a task was woken by either a character being received or a character
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269 being transmitted then we may need to switch to another task. */
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270 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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272 /* End the interrupt in the AIC. */
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273 AT91C_BASE_AIC->AIC_EOICR = 0;
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