2 FreeRTOS V9.0.0 - Copyright (C) 2016 Real Time Engineers Ltd.
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5 VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 This file is part of the FreeRTOS distribution.
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9 FreeRTOS is free software; you can redistribute it and/or modify it under
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10 the terms of the GNU General Public License (version 2) as published by the
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11 Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
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13 ***************************************************************************
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14 >>! NOTE: The modification to the GPL is included to allow you to !<<
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15 >>! distribute a combined work that includes FreeRTOS without being !<<
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16 >>! obliged to provide the source code for proprietary components !<<
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17 >>! outside of the FreeRTOS kernel. !<<
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18 ***************************************************************************
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20 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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21 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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22 FOR A PARTICULAR PURPOSE. Full license text is available on the following
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23 link: http://www.freertos.org/a00114.html
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25 ***************************************************************************
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27 * FreeRTOS provides completely free yet professionally developed, *
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28 * robust, strictly quality controlled, supported, and cross *
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29 * platform software that is more than just the market leader, it *
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30 * is the industry's de facto standard. *
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32 * Help yourself get started quickly while simultaneously helping *
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33 * to support the FreeRTOS project by purchasing a FreeRTOS *
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34 * tutorial book, reference manual, or both: *
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35 * http://www.FreeRTOS.org/Documentation *
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37 ***************************************************************************
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39 http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
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40 the FAQ page "My application does not run, what could be wrong?". Have you
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41 defined configASSERT()?
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43 http://www.FreeRTOS.org/support - In return for receiving this top quality
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44 embedded software for free we request you assist our global community by
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45 participating in the support forum.
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47 http://www.FreeRTOS.org/training - Investing in training allows your team to
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48 be as productive as possible as early as possible. Now you can receive
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49 FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
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50 Ltd, and the world's leading authority on the world's leading RTOS.
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52 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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53 including FreeRTOS+Trace - an indispensable productivity tool, a DOS
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54 compatible FAT file system, and our tiny thread aware UDP/IP stack.
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56 http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
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57 Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
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59 http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
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60 Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
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61 licenses offer ticketed support, indemnification and commercial middleware.
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63 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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64 engineered and independently SIL3 certified version for use in safety and
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65 mission critical applications that require provable dependability.
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71 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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74 /* Library includes. */
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79 /* Scheduler includes. */
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80 #include "FreeRTOS.h"
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83 /* Demo application includes. */
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86 #define UART0_Rx_Pin ( 0x0001<< 8 )
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87 #define UART0_Tx_Pin ( 0x0001<< 9 )
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89 #define serINVALID_QUEUE ( ( QueueHandle_t ) 0 )
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90 #define serNO_BLOCK ( ( TickType_t ) 0 )
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92 /* Macros to turn on and off the Tx empty interrupt. */
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93 #define serINTERRUPT_ON() UART0->IER |= UART_TxHalfEmpty
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94 #define serINTERRUPT_OFF() UART0->IER &= ~UART_TxHalfEmpty
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96 /*-----------------------------------------------------------*/
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98 /* Queues used to hold received characters, and characters waiting to be
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100 static QueueHandle_t xRxedChars;
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101 static QueueHandle_t xCharsForTx;
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103 /*-----------------------------------------------------------*/
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105 /* Interrupt entry point written in the assembler file serialISR.s79. */
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106 extern void vSerialISREntry( void );
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108 /* The interrupt service routine - called from the assembly entry point. */
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109 __arm void vSerialISR( void );
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111 /*-----------------------------------------------------------*/
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114 * See the serial2.h header file.
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116 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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118 xComPortHandle xReturn;
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120 /* Create the queues used to hold Rx and Tx characters. */
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121 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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122 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed char ) );
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124 /* If the queues were created correctly then setup the serial port
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126 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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128 portENTER_CRITICAL();
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130 /* Setup the UART port pins. */
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131 GPIO_Config( GPIO0, UART0_Tx_Pin, GPIO_AF_PP );
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132 GPIO_Config( GPIO0, UART0_Rx_Pin, GPIO_IN_TRI_CMOS );
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134 /* Configure the UART. */
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135 UART_OnOffConfig( UART0, ENABLE );
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136 UART_FifoConfig( UART0, DISABLE );
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137 UART_FifoReset( UART0, UART_RxFIFO );
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138 UART_FifoReset( UART0, UART_TxFIFO );
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139 UART_LoopBackConfig(UART0, DISABLE );
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140 UART_Config( UART0, ulWantedBaud, UART_NO_PARITY, UART_1_StopBits, UARTM_8D );
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141 UART_RxConfig( UART0, ENABLE );
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143 /* Configure the IEC for the UART interrupts. */
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144 EIC_IRQChannelPriorityConfig( UART0_IRQChannel, 1 );
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145 EIC_IRQChannelConfig( UART0_IRQChannel, ENABLE );
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146 EIC_IRQConfig( ENABLE );
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147 UART_ItConfig( UART0, UART_RxBufFull, ENABLE );
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149 portEXIT_CRITICAL();
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153 xReturn = ( xComPortHandle ) 0;
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156 /* This demo file only supports a single port but we have to return
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157 something to comply with the standard demo header file. */
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160 /*-----------------------------------------------------------*/
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162 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, TickType_t xBlockTime )
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164 /* The port handle is not required as this driver only supports one port. */
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167 /* Get the next character from the buffer. Return false if no characters
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168 are available, or arrive before xBlockTime expires. */
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169 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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178 /*-----------------------------------------------------------*/
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180 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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182 signed char *pxNext;
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184 /* A couple of parameters that this port does not use. */
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185 ( void ) usStringLength;
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188 /* NOTE: This implementation does not handle the queue being full as no
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189 block time is used! */
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191 /* The port handle is not required as this driver only supports UART0. */
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194 /* Send each character in the string, one at a time. */
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195 pxNext = ( signed char * ) pcString;
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198 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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202 /*-----------------------------------------------------------*/
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204 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, TickType_t xBlockTime )
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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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226 /*-----------------------------------------------------------*/
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228 /* Serial port ISR. This can cause a context switch so is not defined as a
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229 standard ISR using the __irq keyword. Instead a wrapper function is defined
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230 within serialISR.s79 which in turn calls this function. See the port
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231 documentation on the FreeRTOS.org website for more information. */
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232 __arm void vSerialISR( void )
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234 unsigned short usStatus;
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236 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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238 /* What caused the interrupt? */
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239 usStatus = UART_FlagStatus( UART0 );
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241 if( usStatus & UART_TxHalfEmpty )
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243 /* The interrupt was caused by the THR becoming empty. Are there any
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244 more characters to transmit? */
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245 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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247 /* A character was retrieved from the queue so can be sent to the
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249 UART0->TxBUFR = cChar;
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253 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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254 serINTERRUPT_OFF();
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258 if( usStatus & UART_RxBufFull )
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260 /* The interrupt was caused by a character being received. Grab the
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261 character from the RHR and place it in the queue of received
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263 cChar = UART0->RxBUFR;
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264 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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267 /* If a task was woken by either a character being received or a character
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268 being transmitted then we may need to switch to another task. */
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269 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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271 /* End the interrupt in the EIC. */
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