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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76 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR USART0.
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78 This file contains all the serial port components that can be compiled to
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79 either ARM or THUMB mode. Components that must be compiled to ARM mode are
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80 contained in serialISR.c.
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83 /* Standard includes. */
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86 /* Scheduler includes. */
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87 #include "FreeRTOS.h"
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91 /* Demo application includes. */
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93 #include "AT91R40008.h"
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98 /*-----------------------------------------------------------*/
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100 /* Constants to setup and access the UART. */
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101 #define portUSART0_AIC_CHANNEL ( ( unsigned long ) 2 )
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103 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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104 #define serHANDLE ( ( xComPortHandle ) 1 )
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105 #define serNO_BLOCK ( ( portTickType ) 0 )
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107 /*-----------------------------------------------------------*/
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109 /* Queues used to hold received characters, and characters waiting to be
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111 static xQueueHandle xRxedChars;
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112 static xQueueHandle xCharsForTx;
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114 /*-----------------------------------------------------------*/
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117 * The queues are created in serialISR.c as they are used from the ISR.
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118 * Obtain references to the queues and THRE Empty flag.
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120 extern void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx );
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122 /*-----------------------------------------------------------*/
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124 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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126 unsigned long ulSpeed;
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127 unsigned long ulCD;
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128 xComPortHandle xReturn = serHANDLE;
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129 extern void ( vUART_ISR_Wrapper )( void );
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131 /* The queues are used in the serial ISR routine, so are created from
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132 serialISR.c (which is always compiled to ARM mode. */
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133 vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx );
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136 ( xRxedChars != serINVALID_QUEUE ) &&
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137 ( xCharsForTx != serINVALID_QUEUE ) &&
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138 ( ulWantedBaud != ( unsigned long ) 0 )
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141 portENTER_CRITICAL();
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143 /* Enable clock to USART0... */
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144 AT91C_BASE_PS->PS_PCER = AT91C_PS_US0;
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146 /* Disable all USART0 interrupt sources to begin... */
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147 AT91C_BASE_US0->US_IDR = 0xFFFFFFFF;
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149 /* Reset various status bits (just in case)... */
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150 AT91C_BASE_US0->US_CR = US_RSTSTA;
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152 AT91C_BASE_PIO->PIO_PDR = TXD0 | RXD0; /* Enable RXD and TXD pins */
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153 AT91C_BASE_US0->US_CR = US_RSTRX | US_RSTTX | US_RXDIS | US_TXDIS;
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155 /* Clear Transmit and Receive Counters */
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156 AT91C_BASE_US0->US_RCR = 0;
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157 AT91C_BASE_US0->US_TCR = 0;
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159 /* Input clock to baud rate generator is MCK */
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160 ulSpeed = configCPU_CLOCK_HZ * 10;
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161 ulSpeed = ulSpeed / 16;
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162 ulSpeed = ulSpeed / ulWantedBaud;
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164 /* compute the error */
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165 ulCD = ulSpeed / 10;
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166 if ((ulSpeed - (ulCD * 10)) >= 5)
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169 /* Define the baud rate divisor register */
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170 AT91C_BASE_US0->US_BRGR = ulCD;
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172 /* Define the USART mode */
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173 AT91C_BASE_US0->US_MR = US_CLKS_MCK | US_CHRL_8 | US_PAR_NO | US_NBSTOP_1 | US_CHMODE_NORMAL;
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175 /* Write the Timeguard Register */
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176 AT91C_BASE_US0->US_TTGR = 0;
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178 /* Setup the interrupt for USART0.
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180 Store interrupt handler function address in USART0 vector register... */
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181 AT91C_BASE_AIC->AIC_SVR[ portUSART0_AIC_CHANNEL ] = (unsigned long)vUART_ISR_Wrapper;
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183 /* USART0 interrupt level-sensitive, priority 1... */
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184 AT91C_BASE_AIC->AIC_SMR[ portUSART0_AIC_CHANNEL ] = AIC_SRCTYPE_INT_LEVEL_SENSITIVE | 1;
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186 /* Clear some pending USART0 interrupts (just in case)... */
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187 AT91C_BASE_US0->US_CR = US_RSTSTA;
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189 /* Enable USART0 interrupt sources (but not Tx for now)... */
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190 AT91C_BASE_US0->US_IER = US_RXRDY;
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192 /* Enable USART0 interrupts in the AIC... */
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193 AT91C_BASE_AIC->AIC_IECR = ( 1 << portUSART0_AIC_CHANNEL );
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195 /* Enable receiver and transmitter... */
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196 AT91C_BASE_US0->US_CR = US_RXEN | US_TXEN;
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198 portEXIT_CRITICAL();
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202 xReturn = ( xComPortHandle ) 0;
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207 /*-----------------------------------------------------------*/
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209 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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211 /* The port handle is not required as this driver only supports UART0. */
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214 /* Get the next character from the buffer. Return false if no characters
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215 are available, or arrive before xBlockTime expires. */
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216 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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225 /*-----------------------------------------------------------*/
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227 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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229 signed char *pxNext;
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231 /* NOTE: This implementation does not handle the queue being full as no
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232 block time is used! */
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234 /* The port handle is not required as this driver only supports UART0. */
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236 ( void ) usStringLength;
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238 /* Send each character in the string, one at a time. */
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239 pxNext = ( signed char * ) pcString;
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242 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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246 /*-----------------------------------------------------------*/
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248 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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252 /* Place the character in the queue of characters to be transmitted. */
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253 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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258 /* Turn on the Tx interrupt so the ISR will remove the character from the
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259 queue and send it. This does not need to be in a critical section as
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260 if the interrupt has already removed the character the next interrupt
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261 will simply turn off the Tx interrupt again. */
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262 AT91C_BASE_US0->US_IER = US_TXRDY;
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266 /*-----------------------------------------------------------*/
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268 void vSerialClose( xComPortHandle xPort )
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270 /* Not supported as not required by the demo application. */
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273 /*-----------------------------------------------------------*/
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