2 FreeRTOS.org V4.7.2 - Copyright (C) 2003-2008 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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28 Please ensure to read the configuration and relevant port sections of the
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29 online documentation.
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31 +++ http://www.FreeRTOS.org +++
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32 Documentation, latest information, license and contact details.
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34 +++ http://www.SafeRTOS.com +++
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35 A version that is certified for use in safety critical systems.
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37 +++ http://www.OpenRTOS.com +++
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38 Commercial support, development, porting, licensing and training services.
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40 ***************************************************************************
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46 + Made serial ISR handling more complete and robust.
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50 + Split serial.c into serial.c and serialISR.c. serial.c can be
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51 compiled using ARM or THUMB modes. serialISR.c must always be
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52 compiled in ARM mode.
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53 + Another small change to cSerialPutChar().
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57 + In cSerialPutChar() an extra check is made to ensure the post to
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58 the queue was successful if then attempting to retrieve the posted
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64 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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66 This file contains all the serial port components that can be compiled to
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67 either ARM or THUMB mode. Components that must be compiled to ARM mode are
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68 contained in serialISR.c.
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71 /* Standard includes. */
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74 /* Scheduler includes. */
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75 #include "FreeRTOS.h"
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79 /* Demo application includes. */
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82 /*-----------------------------------------------------------*/
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84 /* Constants to setup and access the UART. */
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85 #define serDLAB ( ( unsigned portCHAR ) 0x80 )
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86 #define serENABLE_INTERRUPTS ( ( unsigned portCHAR ) 0x03 )
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87 #define serNO_PARITY ( ( unsigned portCHAR ) 0x00 )
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88 #define ser1_STOP_BIT ( ( unsigned portCHAR ) 0x00 )
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89 #define ser8_BIT_CHARS ( ( unsigned portCHAR ) 0x03 )
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90 #define serFIFO_ON ( ( unsigned portCHAR ) 0x01 )
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91 #define serCLEAR_FIFO ( ( unsigned portCHAR ) 0x06 )
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92 #define serWANTED_CLOCK_SCALING ( ( unsigned portLONG ) 16 )
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94 /* Constants to setup and access the VIC. */
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95 #define serUART0_VIC_CHANNEL ( ( unsigned portLONG ) 0x0006 )
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96 #define serUART0_VIC_CHANNEL_BIT ( ( unsigned portLONG ) 0x0040 )
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97 #define serUART0_VIC_ENABLE ( ( unsigned portLONG ) 0x0020 )
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98 #define serCLEAR_VIC_INTERRUPT ( ( unsigned portLONG ) 0 )
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100 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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101 #define serHANDLE ( ( xComPortHandle ) 1 )
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102 #define serNO_BLOCK ( ( portTickType ) 0 )
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104 /*-----------------------------------------------------------*/
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106 /* Queues used to hold received characters, and characters waiting to be
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108 static xQueueHandle xRxedChars;
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109 static xQueueHandle xCharsForTx;
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111 /*-----------------------------------------------------------*/
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113 /* Communication flag between the interrupt service routine and serial API. */
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114 static volatile portLONG *plTHREEmpty;
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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, portLONG volatile **pplTHREEmptyFlag );
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122 /*-----------------------------------------------------------*/
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124 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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126 unsigned portLONG ulDivisor, ulWantedClock;
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127 xComPortHandle xReturn = serHANDLE;
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128 extern void ( vUART_ISR_Wrapper )( void );
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130 /* The queues are used in the serial ISR routine, so are created from
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131 serialISR.c (which is always compiled to ARM mode. */
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132 vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx, &plTHREEmpty );
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135 ( xRxedChars != serINVALID_QUEUE ) &&
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136 ( xCharsForTx != serINVALID_QUEUE ) &&
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137 ( ulWantedBaud != ( unsigned portLONG ) 0 )
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140 portENTER_CRITICAL();
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142 /* Setup the baud rate: Calculate the divisor value. */
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143 ulWantedClock = ulWantedBaud * serWANTED_CLOCK_SCALING;
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144 ulDivisor = configCPU_CLOCK_HZ / ulWantedClock;
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146 /* Set the DLAB bit so we can access the divisor. */
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147 UART0_LCR |= serDLAB;
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149 /* Setup the divisor. */
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150 UART0_DLL = ( unsigned portCHAR ) ( ulDivisor & ( unsigned portLONG ) 0xff );
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152 UART0_DLM = ( unsigned portCHAR ) ( ulDivisor & ( unsigned portLONG ) 0xff );
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154 /* Turn on the FIFO's and clear the buffers. */
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155 UART0_FCR = ( serFIFO_ON | serCLEAR_FIFO );
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157 /* Setup transmission format. */
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158 UART0_LCR = serNO_PARITY | ser1_STOP_BIT | ser8_BIT_CHARS;
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160 /* Setup the VIC for the UART. */
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161 VICIntSelect &= ~( serUART0_VIC_CHANNEL_BIT );
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162 VICIntEnable |= serUART0_VIC_CHANNEL_BIT;
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163 VICVectAddr1 = ( portLONG ) vUART_ISR_Wrapper;
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164 VICVectCntl1 = serUART0_VIC_CHANNEL | serUART0_VIC_ENABLE;
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166 /* Enable UART0 interrupts. */
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167 UART0_IER |= serENABLE_INTERRUPTS;
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169 portEXIT_CRITICAL();
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173 xReturn = ( xComPortHandle ) 0;
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178 /*-----------------------------------------------------------*/
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180 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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182 /* The port handle is not required as this driver only supports UART0. */
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185 /* Get the next character from the buffer. Return false if no characters
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186 are available, or arrive before xBlockTime expires. */
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187 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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196 /*-----------------------------------------------------------*/
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198 void vSerialPutString( xComPortHandle pxPort, const signed portCHAR * const pcString, unsigned portSHORT usStringLength )
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200 signed portCHAR *pxNext;
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202 /* NOTE: This implementation does not handle the queue being full as no
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203 block time is used! */
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205 /* The port handle is not required as this driver only supports UART0. */
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207 ( void ) usStringLength;
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209 /* Send each character in the string, one at a time. */
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210 pxNext = ( signed portCHAR * ) pcString;
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213 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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217 /*-----------------------------------------------------------*/
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219 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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221 signed portBASE_TYPE xReturn;
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223 /* This demo driver only supports one port so the parameter is not used. */
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226 portENTER_CRITICAL();
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228 /* Is there space to write directly to the UART? */
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229 if( *plTHREEmpty == ( portLONG ) pdTRUE )
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231 /* We wrote the character directly to the UART, so was
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233 *plTHREEmpty = pdFALSE;
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234 UART0_THR = cOutChar;
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239 /* We cannot write directly to the UART, so queue the character.
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240 Block for a maximum of xBlockTime if there is no space in the
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242 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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244 /* Depending on queue sizing and task prioritisation: While we
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245 were blocked waiting to post interrupts were not disabled. It is
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246 possible that the serial ISR has emptied the Tx queue, in which
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247 case we need to start the Tx off again. */
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248 if( ( *plTHREEmpty == ( portLONG ) pdTRUE ) && ( xReturn == pdPASS ) )
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250 xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
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251 *plTHREEmpty = pdFALSE;
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252 UART0_THR = cOutChar;
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256 portEXIT_CRITICAL();
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260 /*-----------------------------------------------------------*/
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262 void vSerialClose( xComPortHandle xPort )
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264 /* Not supported as not required by the demo application. */
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267 /*-----------------------------------------------------------*/
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