2 FreeRTOS.org V4.1.2 - 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 port 1.
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36 Note that this driver is written to test the RTOS port and is not intended
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37 to represent an optimised solution. In particular no use is made of the DMA
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40 /* Standard include files. */
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43 /* Scheduler include files. */
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44 #include "FreeRTOS.h"
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48 /* Demo application include files. */
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51 /* The queues used to communicate between the task code and the interrupt
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52 service routines. */
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53 static xQueueHandle xRxedChars;
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54 static xQueueHandle xCharsForTx;
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56 /* Hardware specific constants. */
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57 #define serTX_INTERRUPT ( ( unsigned portCHAR ) 0x80 )
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58 #define serRX_INTERRUPT ( ( unsigned portCHAR ) 0x40 )
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59 #define serTX_ENABLE ( ( unsigned portCHAR ) 0x20 )
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60 #define serRX_ENABLE ( ( unsigned portCHAR ) 0x10 )
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62 /* Macros to turn on and off the serial port THRE interrupt while leaving the
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63 other register bits in their correct state. The Rx interrupt is always
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65 #define serTX_INTERRUPT_ON() SCR1 = serTX_INTERRUPT | serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE;
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66 #define serTX_INTERRUPT_OFF() SCR1 = serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE;
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68 /* Bit used to switch on the channel 1 serial port in the module stop
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70 #define serMSTP6 ( ( unsigned portSHORT ) 0x0040 )
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72 /* Interrupt service routines. Note that the Rx and Tx service routines can
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73 cause a context switch and are therefore defined with the saveall attribute in
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74 addition to the interrupt_handler attribute. See the FreeRTOS.org WEB site
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75 documentation for a full explanation.*/
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76 void vCOM_1_Rx_ISR( void ) __attribute__ ( ( saveall, interrupt_handler ) );
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77 void vCOM_1_Tx_ISR( void ) __attribute__ ( ( saveall, interrupt_handler ) );
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78 void vCOM_1_Error_ISR( void ) __attribute__ ( ( interrupt_handler ) );
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80 /*-----------------------------------------------------------*/
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83 * Initialise port 1 for interrupt driven communications.
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85 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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87 /* Create the queues used to communicate between the tasks and the
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88 interrupt service routines. */
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89 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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90 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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92 /* No parity, 8 data bits and 1 stop bit is the default so does not require
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93 configuration - setup the remains of the hardware. */
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94 portENTER_CRITICAL();
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96 /* Turn channel 1 on. */
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97 MSTPCR &= ~serMSTP6;
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99 /* Enable the channels and the Rx interrupt. The Tx interrupt is only
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100 enabled when data is being transmitted. */
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101 SCR1 = serRX_INTERRUPT | serTX_ENABLE | serRX_ENABLE;
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103 /* Bit rate settings for 22.1184MHz clock only!. */
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104 switch( ulWantedBaud )
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106 case 4800 : BRR1 = 143;
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108 case 9600 : BRR1 = 71;
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110 case 19200 : BRR1 = 35;
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112 case 38400 : BRR1 = 17;
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114 case 57600 : BRR1 = 11;
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116 case 115200 : BRR1 = 5;
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118 default : BRR1 = 5;
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122 portEXIT_CRITICAL();
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124 /* Unlike some ports, this driver code does not allow for more than one
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125 com port. We therefore don't return a pointer to a port structure and can
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126 instead just return NULL. */
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129 /*-----------------------------------------------------------*/
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131 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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133 /* Get the next character from the buffer queue. Return false if no characters
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134 are available, or arrive before xBlockTime expires. */
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135 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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144 /*-----------------------------------------------------------*/
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146 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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148 signed portBASE_TYPE xReturn = pdPASS;
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150 /* Return false if after the block time there is no room on the Tx queue. */
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151 portENTER_CRITICAL();
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153 /* Send a character to the queue of characters waiting transmission.
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154 The queue is serviced by the Tx ISR. */
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155 if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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157 /* Could not post onto the queue. */
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162 /* The message was posted onto the queue so we turn on the Tx
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163 interrupt to allow the Tx ISR to remove the character from the
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165 serTX_INTERRUPT_ON();
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168 portEXIT_CRITICAL();
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172 /*-----------------------------------------------------------*/
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174 void vSerialClose( xComPortHandle xPort )
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176 /* Not supported. */
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179 /*-----------------------------------------------------------*/
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181 void vCOM_1_Rx_ISR( void )
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183 /* This can cause a context switch so this macro must be the first line
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184 in the function. */
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185 portENTER_SWITCHING_ISR();
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187 /* As this is a switching ISR the local variables must be declared as
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189 static portCHAR cRxByte;
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190 static portBASE_TYPE xTaskWokenByPost;
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192 /* Get the character. */
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195 /* Post the character onto the queue of received characters - noting
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196 whether or not this wakes a task. */
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197 xTaskWokenByPost = xQueueSendFromISR( xRxedChars, &cRxByte, pdFALSE );
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199 /* Clear the interrupt. */
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200 SSR1 &= ~serRX_INTERRUPT;
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202 /* This must be the last line in the function. We pass cTaskWokenByPost so
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203 a context switch will occur if the received character woke a task that has
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204 a priority higher than the task we interrupted. */
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205 portEXIT_SWITCHING_ISR( xTaskWokenByPost );
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207 /*-----------------------------------------------------------*/
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209 void vCOM_1_Tx_ISR( void )
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211 /* This can cause a context switch so this macro must be the first line
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212 in the function. */
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213 portENTER_SWITCHING_ISR();
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215 /* As this is a switching ISR the local variables must be declared as
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217 static portCHAR cTxByte;
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218 static signed portBASE_TYPE xTaskWokenByTx;
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220 /* This variable is static so must be explicitly reinitialised each
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221 time the function executes. */
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222 xTaskWokenByTx = pdFALSE;
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224 /* The interrupt was caused by the THR becoming empty. Are there any
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225 more characters to transmit? Note whether or not the Tx interrupt has
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227 if( xQueueReceiveFromISR( xCharsForTx, &cTxByte, &xTaskWokenByTx ) == pdTRUE )
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229 /* A character was retrieved from the queue so can be sent to the
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233 /* Clear the interrupt. */
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234 SSR1 &= ~serTX_INTERRUPT;
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238 /* Queue empty, nothing to send so turn off the Tx interrupt. */
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239 serTX_INTERRUPT_OFF();
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242 /* This must be the last line in the function. We pass cTaskWokenByTx so
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243 a context switch will occur if the Tx'ed character woke a task that has
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244 a priority higher than the task we interrupted. */
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245 portEXIT_SWITCHING_ISR( xTaskWokenByTx );
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247 /*-----------------------------------------------------------*/
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250 * This ISR cannot cause a context switch so requires no special
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253 void vCOM_1_Error_ISR( void )
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255 volatile unsigned portCHAR ucIn;
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