2 FreeRTOS V7.5.1 - 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 USART1.
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68 ***Note*** This example uses queues to send each character into an interrupt
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69 service routine and out of an interrupt service routine individually. This
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70 is done to demonstrate queues being used in an interrupt, and to deliberately
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71 load the system to test the FreeRTOS port. It is *NOT* meant to be an
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72 example of an efficient implementation. An efficient implementation should
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73 use FIFO's or DMA if available, and only use FreeRTOS API functions when
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74 enough has been received to warrant a task being unblocked to process the
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78 /* Scheduler includes. */
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79 #include "FreeRTOS.h"
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82 #include "comtest2.h"
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84 /* Library includes. */
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87 /* Demo application includes. */
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88 #include "demo_serial.h"
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89 /*-----------------------------------------------------------*/
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92 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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93 #define serNO_BLOCK ( ( portTickType ) 0 )
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94 #define serPMC_USART_ID ( BOARD_ID_USART )
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96 /* The USART supported by this file. */
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97 #define serUSART_PORT ( USART1 )
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98 #define serUSART_IRQ ( USART1_IRQn )
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100 /* Every bit in the interrupt mask. */
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101 #define serMASK_ALL_INTERRUPTS ( 0xffffffffUL )
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103 /*-----------------------------------------------------------*/
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105 /* The queue used to hold received characters. */
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106 static xQueueHandle xRxedChars;
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107 static xQueueHandle xCharsForTx;
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109 /*-----------------------------------------------------------*/
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113 * See the serial.h header file.
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115 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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118 xComPortHandle xReturn;
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119 const sam_usart_opt_t xUSARTSettings =
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124 US_MR_NBSTOP_1_BIT,
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125 US_MR_CHMODE_NORMAL,
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126 0 /* Only used in IrDA mode. */
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129 /* Create the queues used to hold Rx/Tx characters. */
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130 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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131 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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133 /* If the queues were created correctly then setup the serial port
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135 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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137 /* Enable the peripheral clock in the PMC. */
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138 pmc_enable_periph_clk( serPMC_USART_ID );
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140 /* Configure USART in serial mode. */
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141 usart_init_rs232( serUSART_PORT, &xUSARTSettings, sysclk_get_cpu_hz() );
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143 /* Disable all the interrupts. */
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144 usart_disable_interrupt( serUSART_PORT, serMASK_ALL_INTERRUPTS );
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146 /* Enable the receiver and transmitter. */
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147 usart_enable_tx( serUSART_PORT );
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148 usart_enable_rx( serUSART_PORT );
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150 /* Clear any characters before enabling interrupt. */
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151 usart_getchar( serUSART_PORT, &ulChar );
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153 /* Enable Rx end interrupt. */
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154 usart_enable_interrupt( serUSART_PORT, US_IER_RXRDY );
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156 /* Configure and enable interrupt of USART. */
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157 NVIC_SetPriority( serUSART_IRQ, configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY );
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158 NVIC_EnableIRQ( serUSART_IRQ );
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162 xReturn = ( xComPortHandle ) 0;
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165 /* This demo file only supports a single port but we have to return
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166 something to comply with the standard demo header file. */
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169 /*-----------------------------------------------------------*/
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171 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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173 /* The port handle is not required as this driver only supports one port. */
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176 /* Get the next character from the buffer. Return false if no characters
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177 are available, or arrive before xBlockTime expires. */
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178 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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187 /*-----------------------------------------------------------*/
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189 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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191 signed char *pxNext;
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193 /* A couple of parameters that this port does not use. */
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194 ( void ) usStringLength;
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197 /* NOTE: This implementation does not handle the queue being full as no
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198 block time is used! */
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200 /* The port handle is not required as this driver only supports USART1. */
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203 /* Send each character in the string, one at a time. */
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204 pxNext = ( signed char * ) pcString;
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207 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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211 /*-----------------------------------------------------------*/
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213 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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215 signed portBASE_TYPE xReturn;
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217 /* This simple example only supports one port. */
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220 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) == pdPASS )
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223 usart_enable_interrupt( serUSART_PORT, US_IER_TXRDY );
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232 /*-----------------------------------------------------------*/
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234 void vSerialClose( xComPortHandle xPort )
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236 /* Not supported as not required by the demo application. */
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239 /*-----------------------------------------------------------*/
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242 * It should be noted that the com test tasks (which use make use of this file)
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243 * are included to demonstrate queues being used to communicate between tasks
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244 * and interrupts, and to demonstrate a context switch being performed from
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245 * inside an interrupt service routine. The serial driver used here is *not*
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246 * intended to represent an efficient implementation. Real applications should
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247 * make use of the USARTS peripheral DMA channel (PDC).
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249 void USART1_Handler( void )
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251 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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254 uint32_t ulUSARTStatus, ulUSARTMask;
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256 ulUSARTStatus = usart_get_status( serUSART_PORT );
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257 ulUSARTMask = usart_get_interrupt_mask( serUSART_PORT );
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258 ulUSARTStatus &= ulUSARTMask;
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260 if( ( ulUSARTStatus & US_CSR_TXRDY ) != 0UL )
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262 /* The interrupt was caused by the TX register becoming empty. Are
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263 there any more characters to transmit? */
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264 if( xQueueReceiveFromISR( xCharsForTx, &ucChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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266 /* A character was retrieved from the queue so can be sent to the
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268 usart_putchar( serUSART_PORT, ( uint32_t ) ucChar );
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272 usart_disable_interrupt( serUSART_PORT, US_IER_TXRDY );
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276 if( ( ulUSARTStatus & US_CSR_RXRDY ) != 0UL )
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278 /* A character has been received on the USART, send it to the Rx
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280 usart_getchar( serUSART_PORT, &ulChar );
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281 ucChar = ( uint8_t ) ( ulChar & 0xffUL );
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282 xQueueSendFromISR( xRxedChars, &ucChar, &xHigherPriorityTaskWoken );
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285 /* If sending or receiving from a queue has caused a task to unblock, and
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286 the unblocked task has a priority equal to or higher than the currently
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287 running task (the task this ISR interrupted), then xHigherPriorityTaskWoken
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288 will have automatically been set to pdTRUE within the queue send or receive
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289 function. portEND_SWITCHING_ISR() will then ensure that this ISR returns
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290 directly to the higher priority unblocked task. */
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291 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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