2 FreeRTOS.org V4.0.4 - Copyright (C) 2003-2006 Richard Barry.
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4 This file is part of the FreeRTOS.org distribution.
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6 FreeRTOS.org is free software; you can redistribute it and/or modify
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7 it under the terms of the GNU General Public License as published by
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8 the Free Software Foundation; either version 2 of the License, or
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9 (at your option) any later version.
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11 FreeRTOS.org is distributed in the hope that it will be useful,
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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14 GNU General Public License for more details.
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16 You should have received a copy of the GNU General Public License
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17 along with FreeRTOS.org; if not, write to the Free Software
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18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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20 A special exception to the GPL can be applied should you wish to distribute
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21 a combined work that includes FreeRTOS.org, without being obliged to provide
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22 the source code for any proprietary components. See the licensing section
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23 of http://www.FreeRTOS.org for full details of how and when the exception
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26 ***************************************************************************
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27 See http://www.FreeRTOS.org for documentation, latest information, license
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28 and contact details. Please ensure to read the configuration and relevant
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29 port sections of the online documentation.
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30 ***************************************************************************
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34 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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37 /* Library includes. */
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42 /* Scheduler includes. */
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43 #include "FreeRTOS.h"
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46 /* Demo application includes. */
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49 #define UART0_Rx_Pin ( 0x0001<< 8 )
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50 #define UART0_Tx_Pin ( 0x0001<< 9 )
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52 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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53 #define serNO_BLOCK ( ( portTickType ) 0 )
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55 /* Macros to turn on and off the Tx empty interrupt. */
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56 #define serINTERRUPT_ON() UART0->IER |= UART_TxHalfEmpty
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57 #define serINTERRUPT_OFF() UART0->IER &= ~UART_TxHalfEmpty
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59 /*-----------------------------------------------------------*/
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61 /* Queues used to hold received characters, and characters waiting to be
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63 static xQueueHandle xRxedChars;
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64 static xQueueHandle xCharsForTx;
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66 /*-----------------------------------------------------------*/
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68 /* Interrupt entry point written in the assembler file serialISR.s79. */
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69 extern void vSerialISREntry( void );
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71 /* The interrupt service routine - called from the assembly entry point. */
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72 __arm void vSerialISR( void );
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74 /*-----------------------------------------------------------*/
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77 * See the serial2.h header file.
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79 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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81 xComPortHandle xReturn;
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83 /* Create the queues used to hold Rx and Tx characters. */
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84 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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85 xCharsForTx = xQueueCreate( uxQueueLength + 1, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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87 /* If the queues were created correctly then setup the serial port
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89 if( ( xRxedChars != serINVALID_QUEUE ) && ( xCharsForTx != serINVALID_QUEUE ) )
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91 portENTER_CRITICAL();
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93 /* Setup the UART port pins. */
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94 GPIO_Config( GPIO0, UART0_Tx_Pin, GPIO_AF_PP );
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95 GPIO_Config( GPIO0, UART0_Rx_Pin, GPIO_IN_TRI_CMOS );
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97 /* Configure the UART. */
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98 UART_OnOffConfig( UART0, ENABLE );
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99 UART_FifoConfig( UART0, DISABLE );
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100 UART_FifoReset( UART0, UART_RxFIFO );
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101 UART_FifoReset( UART0, UART_TxFIFO );
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102 UART_LoopBackConfig(UART0, DISABLE );
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103 UART_Config( UART0, ulWantedBaud, UART_NO_PARITY, UART_1_StopBits, UARTM_8D );
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104 UART_RxConfig( UART0, ENABLE );
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106 /* Configure the IEC for the UART interrupts. */
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107 EIC_IRQChannelPriorityConfig( UART0_IRQChannel, 1 );
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108 EIC_IRQChannelConfig( UART0_IRQChannel, ENABLE );
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109 EIC_IRQConfig( ENABLE );
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110 UART_ItConfig( UART0, UART_RxBufFull, ENABLE );
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112 portEXIT_CRITICAL();
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116 xReturn = ( xComPortHandle ) 0;
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119 /* This demo file only supports a single port but we have to return
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120 something to comply with the standard demo header file. */
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123 /*-----------------------------------------------------------*/
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125 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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127 /* The port handle is not required as this driver only supports one port. */
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130 /* Get the next character from the buffer. Return false if no characters
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131 are available, or arrive before xBlockTime expires. */
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132 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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141 /*-----------------------------------------------------------*/
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143 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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145 signed portCHAR *pxNext;
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147 /* A couple of parameters that this port does not use. */
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148 ( void ) usStringLength;
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151 /* NOTE: This implementation does not handle the queue being full as no
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152 block time is used! */
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154 /* The port handle is not required as this driver only supports UART0. */
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157 /* Send each character in the string, one at a time. */
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158 pxNext = ( signed portCHAR * ) pcString;
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161 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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165 /*-----------------------------------------------------------*/
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167 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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169 /* Place the character in the queue of characters to be transmitted. */
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170 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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175 /* Turn on the Tx interrupt so the ISR will remove the character from the
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176 queue and send it. This does not need to be in a critical section as
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177 if the interrupt has already removed the character the next interrupt
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178 will simply turn off the Tx interrupt again. */
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183 /*-----------------------------------------------------------*/
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185 void vSerialClose( xComPortHandle xPort )
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187 /* Not supported as not required by the demo application. */
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189 /*-----------------------------------------------------------*/
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191 /* Serial port ISR. This can cause a context switch so is not defined as a
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192 standard ISR using the __irq keyword. Instead a wrapper function is defined
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193 within serialISR.s79 which in turn calls this function. See the port
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194 documentation on the FreeRTOS.org website for more information. */
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195 __arm void vSerialISR( void )
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197 unsigned portSHORT usStatus;
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198 signed portCHAR cChar;
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199 portBASE_TYPE xTaskWokenByTx = pdFALSE, xTaskWokenByPost = pdFALSE;
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201 /* What caused the interrupt? */
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202 usStatus = UART_FlagStatus( UART0 );
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204 if( usStatus & UART_TxHalfEmpty )
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206 /* The interrupt was caused by the THR becoming empty. Are there any
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207 more characters to transmit? */
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208 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWokenByTx ) == pdTRUE )
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210 /* A character was retrieved from the queue so can be sent to the
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212 UART0->TxBUFR = cChar;
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216 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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217 serINTERRUPT_OFF();
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221 if( usStatus & UART_RxBufFull )
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223 /* The interrupt was caused by a character being received. Grab the
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224 character from the RHR and place it in the queue of received
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226 cChar = UART0->RxBUFR;
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227 xTaskWokenByPost = xQueueSendFromISR( xRxedChars, &cChar, xTaskWokenByPost );
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230 /* If a task was woken by either a character being received or a character
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231 being transmitted then we may need to switch to another task. */
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232 portEND_SWITCHING_ISR( ( xTaskWokenByPost || xTaskWokenByTx ) );
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234 /* End the interrupt in the EIC. */
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