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 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 /* Library includes. */
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80 #include "usart/usart.h"
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81 #include "pmc/pmc.h"
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82 #include "irq/irq.h"
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83 #include "pio/pio.h"
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85 /*-----------------------------------------------------------*/
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87 /* Interrupt control macros. */
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88 #define serINTERRUPT_LEVEL ( 5 )
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89 #define vInterruptOn() BOARD_USART_BASE->US_IER = ( AT91C_US_TXRDY | AT91C_US_RXRDY )
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90 #define vInterruptOff() BOARD_USART_BASE->US_IDR = AT91C_US_TXRDY
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92 /* Misc constants. */
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93 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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94 #define serHANDLE ( ( xComPortHandle ) 1 )
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95 #define serNO_BLOCK ( ( portTickType ) 0 )
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96 #define serNO_TIMEGUARD ( ( unsigned long ) 0 )
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97 #define serNO_PERIPHERAL_B_SETUP ( ( unsigned long ) 0 )
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100 /* Queues used to hold received characters, and characters waiting to be
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102 static xQueueHandle xRxedChars;
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103 static xQueueHandle xCharsForTx;
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105 /*-----------------------------------------------------------*/
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107 /* The interrupt service routine - called from the assembly entry point. */
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108 void vSerialISR( void );
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110 /*-----------------------------------------------------------*/
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113 * See the serial2.h header file.
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115 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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117 xComPortHandle xReturn = serHANDLE;
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118 extern void ( vUART_ISR )( void );
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119 const Pin xUSART_Pins[] = { BOARD_PIN_USART_RXD, BOARD_PIN_USART_TXD };
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122 /* Create the queues used to hold Rx and Tx characters. */
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123 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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124 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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126 /* If the queues were created correctly then setup the serial port
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128 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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130 portENTER_CRITICAL();
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132 /* Enable the peripheral clock in the PMC. */
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133 PMC_EnablePeripheral( BOARD_ID_USART );
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135 /* Configure the USART. */
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136 USART_Configure( BOARD_USART_BASE, AT91C_US_CHRL_8_BITS | AT91C_US_PAR_NONE | AT91C_US_NBSTOP_1_BIT, ulWantedBaud, configCPU_CLOCK_HZ );
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138 /* Configure the interrupt. Note the pre-emption priority is set
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139 in bits [8:15] of the priority value passed as the parameter. */
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140 IRQ_ConfigureIT( BOARD_ID_USART, ( configMAX_SYSCALL_INTERRUPT_PRIORITY << 8 ), vSerialISR );
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141 IRQ_EnableIT( BOARD_ID_USART );
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143 /* Enable receiver & transmitter. */
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144 USART_SetTransmitterEnabled( BOARD_USART_BASE, pdTRUE );
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145 USART_SetReceiverEnabled( BOARD_USART_BASE, pdTRUE );
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147 /* Configure IO for USART use. */
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148 PIO_Configure( xUSART_Pins, PIO_LISTSIZE( xUSART_Pins ) );
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150 portEXIT_CRITICAL();
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154 xReturn = ( xComPortHandle ) 0;
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157 /* This demo file only supports a single port but we have to return
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158 something to comply with the standard demo header file. */
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161 /*-----------------------------------------------------------*/
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163 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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165 /* The port handle is not required as this driver only supports one port. */
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168 /* Get the next character from the buffer. Return false if no characters
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169 are available, or arrive before xBlockTime expires. */
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170 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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179 /*-----------------------------------------------------------*/
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181 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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183 signed char *pxNext;
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185 /* A couple of parameters that this port does not use. */
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186 ( void ) usStringLength;
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189 /* NOTE: This implementation does not handle the queue being full as no
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190 block time is used! */
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192 /* The port handle is not required as this driver only supports UART0. */
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195 /* Send each character in the string, one at a time. */
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196 pxNext = ( signed char * ) pcString;
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199 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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203 /*-----------------------------------------------------------*/
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205 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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207 /* Place the character in the queue of characters to be transmitted. */
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208 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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213 /* Turn on the Tx interrupt so the ISR will remove the character from the
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214 queue and send it. This does not need to be in a critical section as
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215 if the interrupt has already removed the character the next interrupt
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216 will simply turn off the Tx interrupt again. */
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221 /*-----------------------------------------------------------*/
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223 void vSerialClose( xComPortHandle xPort )
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225 /* Not supported as not required by the demo application. */
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227 /*-----------------------------------------------------------*/
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229 void vSerialISR( void )
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231 unsigned long ulStatus;
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233 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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235 /* What caused the interrupt? */
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236 ulStatus = BOARD_USART_BASE->US_CSR &= BOARD_USART_BASE->US_IMR;
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238 if( ulStatus & AT91C_US_TXRDY )
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240 /* The interrupt was caused by the THR becoming empty. Are there any
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241 more characters to transmit? */
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242 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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244 /* A character was retrieved from the queue so can be sent to the
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246 BOARD_USART_BASE->US_THR = cChar;
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250 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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255 if( ulStatus & AT91C_US_RXRDY )
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257 /* The interrupt was caused by a character being received. Grab the
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258 character from the RHR and place it in the queue or received
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260 cChar = BOARD_USART_BASE->US_RHR;
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261 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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264 /* If a task was woken by either a character being received or a character
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265 being transmitted then we may need to switch to another task. */
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266 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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