2 FreeRTOS.org V5.1.2 - Copyright (C) 2003-2009 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 ***************************************************************************
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29 * Get the FreeRTOS eBook! See http://www.FreeRTOS.org/Documentation *
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31 * This is a concise, step by step, 'hands on' guide that describes both *
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32 * general multitasking concepts and FreeRTOS specifics. It presents and *
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33 * explains numerous examples that are written using the FreeRTOS API. *
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34 * Full source code for all the examples is provided in an accompanying *
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37 ***************************************************************************
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38 ***************************************************************************
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40 Please ensure to read the configuration and relevant port sections of the
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41 online documentation.
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43 http://www.FreeRTOS.org - Documentation, latest information, license and
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46 http://www.SafeRTOS.com - A version that is certified for use in safety
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49 http://www.OpenRTOS.com - Commercial support, development, porting,
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50 licensing and training services.
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54 /* Standard includes. */
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57 /* Scheduler include files. */
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58 #include "FreeRTOS.h"
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62 /* Application includes. */
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65 /*-----------------------------------------------------------*/
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67 /* Constants to setup the microcontroller IO. */
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68 #define mainSDA_ENABLE ( ( unsigned portLONG ) 0x0040 )
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69 #define mainSCL_ENABLE ( ( unsigned portLONG ) 0x0010 )
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71 /* Bit definitions within the I2CONCLR register. */
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72 #define i2cSTA_BIT ( ( unsigned portCHAR ) 0x20 )
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73 #define i2cSI_BIT ( ( unsigned portCHAR ) 0x08 )
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74 #define i2cSTO_BIT ( ( unsigned portCHAR ) 0x10 )
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76 /* Constants required to setup the VIC. */
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77 #define i2cI2C_VIC_CHANNEL ( ( unsigned portLONG ) 0x0009 )
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78 #define i2cI2C_VIC_CHANNEL_BIT ( ( unsigned portLONG ) 0x0200 )
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79 #define i2cI2C_VIC_ENABLE ( ( unsigned portLONG ) 0x0020 )
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81 /* Misc constants. */
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82 #define i2cNO_BLOCK ( ( portTickType ) 0 )
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83 #define i2cQUEUE_LENGTH ( ( unsigned portCHAR ) 5 )
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84 #define i2cEXTRA_MESSAGES ( ( unsigned portCHAR ) 2 )
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85 #define i2cREAD_TX_LEN ( ( unsigned portLONG ) 2 )
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86 #define i2cACTIVE_MASTER_MODE ( ( unsigned portCHAR ) 0x40 )
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87 #define i2cTIMERL ( 200 )
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88 #define i2cTIMERH ( 200 )
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90 /* Array of message definitions. See the header file for more information
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91 on the structure members. There are two more places in the queue than as
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92 defined by i2cQUEUE_LENGTH. This is to ensure that there is always a free
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93 message available - one can be in the process of being transmitted and one
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94 can be left free. */
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95 static xI2CMessage xTxMessages[ i2cQUEUE_LENGTH + i2cEXTRA_MESSAGES ];
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97 /* Function in the ARM part of the code used to create the queues. */
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98 extern void vI2CISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxTxMessages, unsigned portLONG **ppulBusFree );
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100 /* Index to the next free message in the xTxMessages array. */
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101 unsigned portLONG ulNextFreeMessage = ( unsigned portLONG ) 0;
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103 /* Queue of messages that are waiting transmission. */
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104 static xQueueHandle xMessagesForTx;
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106 /* Flag to indicate the state of the I2C ISR state machine. */
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107 static unsigned portLONG *pulBusFree;
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109 /*-----------------------------------------------------------*/
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110 void i2cMessage( const unsigned portCHAR * const pucMessage, portLONG lMessageLength, unsigned portCHAR ucSlaveAddress, unsigned portSHORT usBufferAddress, unsigned portLONG ulDirection, xSemaphoreHandle xMessageCompleteSemaphore, portTickType xBlockTime )
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112 extern volatile xI2CMessage *pxCurrentMessage;
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113 xI2CMessage *pxNextFreeMessage;
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114 signed portBASE_TYPE xReturn;
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116 portENTER_CRITICAL();
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118 /* This message is guaranteed to be free as there are two more messages
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119 than spaces in the queue allowing for one message to be in process of
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120 being transmitted and one to be left free. */
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121 pxNextFreeMessage = &( xTxMessages[ ulNextFreeMessage ] );
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123 /* Fill the message with the data to be sent. */
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125 /* Pointer to the actual data. Only a pointer is stored (i.e. the
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126 actual data is not copied, so the data being pointed to must still
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127 be valid when the message eventually gets sent (it may be queued for
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129 pxNextFreeMessage->pucBuffer = ( unsigned portCHAR * ) pucMessage;
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131 /* This is the address of the I2C device we are going to transmit this
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133 pxNextFreeMessage->ucSlaveAddress = ucSlaveAddress | ( unsigned portCHAR ) ulDirection;
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135 /* A semaphore can be used to allow the I2C ISR to indicate that the
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136 message has been sent. This can be NULL if you don't want to wait for
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137 the message transmission to complete. */
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138 pxNextFreeMessage->xMessageCompleteSemaphore = xMessageCompleteSemaphore;
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140 /* How many bytes are to be sent? */
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141 pxNextFreeMessage->lMessageLength = lMessageLength;
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143 /* The address within the WIZnet device to which the data will be
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144 written. This could be the address of a register, or alternatively
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145 a location within the WIZnet Tx buffer. */
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146 pxNextFreeMessage->ucBufferAddressLowByte = ( unsigned portCHAR ) ( usBufferAddress & 0xff );
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148 /* Second byte of the address. */
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149 usBufferAddress >>= 8;
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150 pxNextFreeMessage->ucBufferAddressHighByte = ( unsigned portCHAR ) ( usBufferAddress & 0xff );
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152 /* Increment to the next message in the array - with a wrap around check. */
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153 ulNextFreeMessage++;
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154 if( ulNextFreeMessage >= ( i2cQUEUE_LENGTH + i2cEXTRA_MESSAGES ) )
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156 ulNextFreeMessage = ( unsigned portLONG ) 0;
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159 /* Is the I2C interrupt in the middle of transmitting a message? */
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160 if( *pulBusFree == ( unsigned portLONG ) pdTRUE )
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162 /* No message is currently being sent or queued to be sent. We
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163 can start the ISR sending this message immediately. */
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164 pxCurrentMessage = pxNextFreeMessage;
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166 I2C_I2CONCLR = i2cSI_BIT;
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167 I2C_I2CONSET = i2cSTA_BIT;
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169 *pulBusFree = ( unsigned portLONG ) pdFALSE;
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173 /* The I2C interrupt routine is mid sending a message. Queue
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174 this message ready to be sent. */
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175 xReturn = xQueueSend( xMessagesForTx, &pxNextFreeMessage, xBlockTime );
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177 /* We may have blocked while trying to queue the message. If this
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178 was the case then the interrupt would have been enabled and we may
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179 now find that the I2C interrupt routine is no longer sending a
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181 if( ( *pulBusFree == ( unsigned portLONG ) pdTRUE ) && ( xReturn == pdPASS ) )
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183 /* Get the next message in the queue (this should be the
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184 message we just posted) and start off the transmission
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186 xQueueReceive( xMessagesForTx, &pxNextFreeMessage, i2cNO_BLOCK );
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187 pxCurrentMessage = pxNextFreeMessage;
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189 I2C_I2CONCLR = i2cSI_BIT;
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190 I2C_I2CONSET = i2cSTA_BIT;
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192 *pulBusFree = ( unsigned portLONG ) pdFALSE;
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196 portEXIT_CRITICAL();
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198 /*-----------------------------------------------------------*/
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200 void i2cInit( void )
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202 extern void ( vI2C_ISR_Wrapper )( void );
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204 /* Create the queue used to send messages to the ISR. */
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205 vI2CISRCreateQueues( i2cQUEUE_LENGTH, &xMessagesForTx, &pulBusFree );
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207 /* Configure the I2C hardware. */
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209 I2C_I2CONCLR = 0xff;
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211 PCB_PINSEL0 |= mainSDA_ENABLE;
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212 PCB_PINSEL0 |= mainSCL_ENABLE;
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214 I2C_I2SCLL = i2cTIMERL;
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215 I2C_I2SCLH = i2cTIMERH;
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216 I2C_I2CONSET = i2cACTIVE_MASTER_MODE;
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218 portENTER_CRITICAL();
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220 /* Setup the VIC for the i2c interrupt. */
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221 VICIntSelect &= ~( i2cI2C_VIC_CHANNEL_BIT );
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222 VICIntEnable |= i2cI2C_VIC_CHANNEL_BIT;
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223 VICVectAddr2 = ( portLONG ) vI2C_ISR_Wrapper;
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225 VICVectCntl2 = i2cI2C_VIC_CHANNEL | i2cI2C_VIC_ENABLE;
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227 portEXIT_CRITICAL();
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