git.sur5r.net Git - freertos/blob - FreeRTOS/Demo/WizNET_DEMO_GCC_ARM7/i2cISR.c

   1 /*\r
   2     FreeRTOS V8.0.0 - Copyright (C) 2014 Real Time Engineers Ltd. \r
   3     All rights reserved\r
   4 \r
   5     VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.\r
   6 \r
   7     ***************************************************************************\r
   8      *                                                                       *\r
   9      *    FreeRTOS provides completely free yet professionally developed,    *\r
  10      *    robust, strictly quality controlled, supported, and cross          *\r
  11      *    platform software that has become a de facto standard.             *\r
  12      *                                                                       *\r
  13      *    Help yourself get started quickly and support the FreeRTOS         *\r
  14      *    project by purchasing a FreeRTOS tutorial book, reference          *\r
  15      *    manual, or both from: http://www.FreeRTOS.org/Documentation        *\r
  16      *                                                                       *\r
  17      *    Thank you!                                                         *\r
  18      *                                                                       *\r
  19     ***************************************************************************\r
  20 \r
  21     This file is part of the FreeRTOS distribution.\r
  22 \r
  23     FreeRTOS is free software; you can redistribute it and/or modify it under\r
  24     the terms of the GNU General Public License (version 2) as published by the\r
  25     Free Software Foundation >>!AND MODIFIED BY!<< the FreeRTOS exception.\r
  26 \r
  27     >>! NOTE: The modification to the GPL is included to allow you to distribute\r
  28     >>! a combined work that includes FreeRTOS without being obliged to provide\r
  29     >>! the source code for proprietary components outside of the FreeRTOS\r
  30     >>! kernel.\r
  31 \r
  32     FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY\r
  33     WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS\r
  34     FOR A PARTICULAR PURPOSE.  Full license text is available from the following\r
  35     link: http://www.freertos.org/a00114.html\r
  36 \r
  37     1 tab == 4 spaces!\r
  38 \r
  39     ***************************************************************************\r
  40      *                                                                       *\r
  41      *    Having a problem?  Start by reading the FAQ "My application does   *\r
  42      *    not run, what could be wrong?"                                     *\r
  43      *                                                                       *\r
  44      *    http://www.FreeRTOS.org/FAQHelp.html                               *\r
  45      *                                                                       *\r
  46     ***************************************************************************\r
  47 \r
  48     http://www.FreeRTOS.org - Documentation, books, training, latest versions,\r
  49     license and Real Time Engineers Ltd. contact details.\r
  50 \r
  51     http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,\r
  52     including FreeRTOS+Trace - an indispensable productivity tool, a DOS\r
  53     compatible FAT file system, and our tiny thread aware UDP/IP stack.\r
  54 \r
  55     http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High\r
  56     Integrity Systems to sell under the OpenRTOS brand.  Low cost OpenRTOS\r
  57     licenses offer ticketed support, indemnification and middleware.\r
  58 \r
  59     http://www.SafeRTOS.com - High Integrity Systems also provide a safety\r
  60     engineered and independently SIL3 certified version for use in safety and\r
  61     mission critical applications that require provable dependability.\r
  62 \r
  63     1 tab == 4 spaces!\r
  64 */\r
  65 \r
  66 \r
  67 /* Standard includes. */\r
  68 #include <stdlib.h>\r
  69 \r
  70 /* Scheduler include files. */\r
  71 #include "FreeRTOS.h"\r
  72 #include "task.h"\r
  73 #include "queue.h"\r
  74 #include "semphr.h"\r
  75 \r
  76 /* Application includes. */\r
  77 #include "i2c.h"\r
  78 \r
  79 /*-----------------------------------------------------------*/\r
  80 \r
  81 /* Bit definitions within the I2CONCLR register. */\r
  82 #define i2cSTA_BIT              ( ( unsigned char ) 0x20 )\r
  83 #define i2cSI_BIT               ( ( unsigned char ) 0x08 )\r
  84 #define i2cSTO_BIT              ( ( unsigned char ) 0x10 )\r
  85 #define i2cAA_BIT               ( ( unsigned char ) 0x04 )\r
  86 \r
  87 /* Status codes for the I2STAT register. */\r
  88 #define i2cSTATUS_START_TXED                    ( 0x08 )\r
  89 #define i2cSTATUS_REP_START_TXED                ( 0x10 )\r
  90 #define i2cSTATUS_TX_ADDR_ACKED                 ( 0x18 )\r
  91 #define i2cSTATUS_DATA_TXED                             ( 0x28 )\r
  92 #define i2cSTATUS_RX_ADDR_ACKED                 ( 0x40 )\r
  93 #define i2cSTATUS_DATA_RXED                             ( 0x50 )\r
  94 #define i2cSTATUS_LAST_BYTE_RXED                ( 0x58 )\r
  95 \r
  96 /* Constants for operation of the VIC. */\r
  97 #define i2cCLEAR_VIC_INTERRUPT  ( 0 )\r
  98 \r
  99 /* Misc constants. */\r
 100 #define i2cJUST_ONE_BYTE_TO_RX  ( 1 )\r
 101 #define i2cBUFFER_ADDRESS_BYTES ( 2 )\r
 102 \r
 103 /* End the current transmission and free the bus. */\r
 104 #define i2cEND_TRANSMISSION( lStatus )                                  \\r
 105 {                                                                                                               \\r
 106         I2C_I2CONCLR = i2cAA_BIT;                                                       \\r
 107         I2C_I2CONSET = i2cSTO_BIT;                                                      \\r
 108         eCurrentState = eSentStart;                                                     \\r
 109         lTransactionCompleted = lStatus;                                        \\r
 110 }\r
 111 /*-----------------------------------------------------------*/\r
 112 \r
 113 /* Valid i2c communication states. */\r
 114 typedef enum\r
 115 {\r
 116         eSentStart,                             /*<< Last action was the transmission of a start bit. */\r
 117         eSentAddressForWrite,   /*<< Last action was the transmission of the slave address we are to write to. */\r
 118         eSentAddressForRead,    /*<< Last action was the transmission of the slave address we are to read from. */\r
 119         eSentData,                              /*<< Last action was the transmission of a data byte. */\r
 120         eReceiveData                    /*<< We expected data to be received. */\r
 121 } I2C_STATE;\r
 122 /*-----------------------------------------------------------*/\r
 123 \r
 124 /* Points to the message currently being sent. */\r
 125 volatile xI2CMessage *pxCurrentMessage = NULL;  \r
 126 \r
 127 /* The queue of messages waiting to be transmitted. */\r
 128 static QueueHandle_t xMessagesForTx;\r
 129 \r
 130 /* Flag used to indicate whether or not the ISR is amid sending a message. */\r
 131 unsigned long ulBusFree = ( unsigned long ) pdTRUE;\r
 132 \r
 133 /* Setting this to true will cause the TCP task to think a message is \r
 134 complete and thus restart.  It can therefore be used under error states\r
 135 to force a restart. */\r
 136 volatile long lTransactionCompleted = pdTRUE;\r
 137 \r
 138 /*-----------------------------------------------------------*/\r
 139 \r
 140 void vI2CISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, QueueHandle_t *pxTxMessages, unsigned long **ppulBusFree )\r
 141 {\r
 142         /* Create the queues used to hold Rx and Tx characters. */\r
 143         xMessagesForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( xI2CMessage * ) );\r
 144 \r
 145         /* Pass back a reference to the queue and bus free flag so the I2C API file \r
 146         can post messages. */\r
 147         *pxTxMessages = xMessagesForTx;\r
 148         *ppulBusFree = &ulBusFree;\r
 149 }\r
 150 /*-----------------------------------------------------------*/\r
 151 \r
 152 /* The ISR entry point. */\r
 153 void vI2C_ISR_Wrapper( void ) __attribute__ (( naked ));\r
 154 \r
 155 /* The ISR function to perform the actual work.  This must be a separate\r
 156 function from the wrapper to ensure the correct stack frame is set up. */\r
 157 void vI2C_ISR_Handler( void );\r
 158 \r
 159 /*-----------------------------------------------------------*/\r
 160 \r
 161 void vI2C_ISR_Wrapper( void )\r
 162 {\r
 163         /* Save the context of the interrupted task. */\r
 164         portSAVE_CONTEXT();\r
 165 \r
 166         /* Call the handler to perform the actual work.  This must be a\r
 167         separate function to ensure the correct stack frame is set up. */\r
 168         vI2C_ISR_Handler();\r
 169 \r
 170         /* Restore the context of whichever task is going to run next. */\r
 171         portRESTORE_CONTEXT();\r
 172 }\r
 173 /*-----------------------------------------------------------*/\r
 174 \r
 175 void vI2C_ISR_Handler( void )\r
 176 {\r
 177 /* Holds the current transmission state. */                                                     \r
 178 static I2C_STATE eCurrentState = eSentStart;\r
 179 static long lMessageIndex = -i2cBUFFER_ADDRESS_BYTES; /* There are two address bytes to send prior to the data. */\r
 180 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;\r
 181 long lBytesLeft;\r
 182 \r
 183         /* The action taken for this interrupt depends on our current state. */\r
 184         switch( eCurrentState )\r
 185         {\r
 186                 case eSentStart :       \r
 187 \r
 188                                 /* We sent a start bit, if it was successful we can\r
 189                                 go on to send the slave address. */\r
 190                                 if( ( I2C_I2STAT == i2cSTATUS_START_TXED ) || ( I2C_I2STAT == i2cSTATUS_REP_START_TXED ) )\r
 191                                 {\r
 192                                         /* Send the slave address. */\r
 193                                         I2C_I2DAT = pxCurrentMessage->ucSlaveAddress;\r
 194 \r
 195                                         if( pxCurrentMessage->ucSlaveAddress & i2cREAD )\r
 196                                         {\r
 197                                                 /* We are then going to read bytes back from the \r
 198                                                 slave. */\r
 199                                                 eCurrentState = eSentAddressForRead;\r
 200                                                 \r
 201                                                 /* Initialise the buffer index so the first byte goes\r
 202                                                 into the first buffer position. */\r
 203                                                 lMessageIndex = 0;\r
 204                                         }\r
 205                                         else\r
 206                                         {\r
 207                                                 /* We are then going to write some data to the slave. */\r
 208                                                 eCurrentState = eSentAddressForWrite;\r
 209 \r
 210                                                 /* When writing bytes we first have to send the two\r
 211                                                 byte buffer address so lMessageIndex is set negative,\r
 212                                                 when it reaches 0 it is time to send the actual data. */\r
 213                                                 lMessageIndex = -i2cBUFFER_ADDRESS_BYTES;\r
 214                                         }\r
 215                                 }\r
 216                                 else\r
 217                                 {\r
 218                                         /* Could not send the start bit so give up. */\r
 219                                         i2cEND_TRANSMISSION( pdFAIL );                                  \r
 220                                 }\r
 221 \r
 222                                 I2C_I2CONCLR = i2cSTA_BIT;                              \r
 223 \r
 224                                 break;\r
 225 \r
 226                 case eSentAddressForWrite :\r
 227 \r
 228                                 /* We sent the address of the slave we are going to write to.\r
 229                                 If this was acknowledged we     can go on to send the data. */\r
 230                                 if( I2C_I2STAT == i2cSTATUS_TX_ADDR_ACKED )\r
 231                                 {\r
 232                                         /* Start the first byte transmitting which is the \r
 233                                         first byte of the buffer address to which the data will \r
 234                                         be sent. */\r
 235                                         I2C_I2DAT = pxCurrentMessage->ucBufferAddressHighByte;\r
 236                                         eCurrentState = eSentData;\r
 237                                 }\r
 238                                 else\r
 239                                 {\r
 240                                         /* Address was not acknowledged so give up. */\r
 241                                         i2cEND_TRANSMISSION( pdFAIL );                                  \r
 242                                 }                                       \r
 243                                 break;\r
 244 \r
 245                 case eSentAddressForRead :\r
 246 \r
 247                                 /* We sent the address of the slave we are going to read from.\r
 248                                 If this was acknowledged we can go on to read the data. */\r
 249                                 if( I2C_I2STAT == i2cSTATUS_RX_ADDR_ACKED )\r
 250                                 {\r
 251                                         eCurrentState = eReceiveData;\r
 252                                         if( pxCurrentMessage->lMessageLength > i2cJUST_ONE_BYTE_TO_RX )\r
 253                                         {\r
 254                                                 /* Don't ack the last byte of the message. */\r
 255                                                 I2C_I2CONSET = i2cAA_BIT;\r
 256                                         }                                       \r
 257                                 }\r
 258                                 else\r
 259                                 {\r
 260                                         /* Something unexpected happened - give up. */\r
 261                                         i2cEND_TRANSMISSION( pdFAIL );                                  \r
 262                                 }\r
 263                                 break;\r
 264 \r
 265                 case eReceiveData :\r
 266                                 \r
 267                                 /* We have just received a byte from the slave. */\r
 268                                 if( ( I2C_I2STAT == i2cSTATUS_DATA_RXED ) || ( I2C_I2STAT == i2cSTATUS_LAST_BYTE_RXED ) )\r
 269                                 {\r
 270                                         /* Buffer the byte just received then increment the index \r
 271                                         so it points to the next free space. */\r
 272                                         pxCurrentMessage->pucBuffer[ lMessageIndex ] = I2C_I2DAT;\r
 273                                         lMessageIndex++;\r
 274 \r
 275                                         /* How many more bytes are we expecting to receive? */\r
 276                                         lBytesLeft = pxCurrentMessage->lMessageLength - lMessageIndex;\r
 277                                         if( lBytesLeft == ( unsigned long ) 0 )\r
 278                                         {\r
 279                                                 /* This was the last byte in the message. */\r
 280                                                 i2cEND_TRANSMISSION( pdPASS );\r
 281 \r
 282                                                 /* If xMessageCompleteSemaphore is not null then there\r
 283                                                 is a task waiting for this message to complete and we\r
 284                                                 must 'give' the semaphore so the task is woken.*/\r
 285                                                 if( pxCurrentMessage->xMessageCompleteSemaphore )\r
 286                                                 {\r
 287                                                         xSemaphoreGiveFromISR( pxCurrentMessage->xMessageCompleteSemaphore, &xHigherPriorityTaskWoken );\r
 288                                                 }\r
 289 \r
 290                                                 /* Are there any other messages to transact? */\r
 291                                                 if( xQueueReceiveFromISR( xMessagesForTx, &pxCurrentMessage, &xHigherPriorityTaskWoken ) == pdTRUE )\r
 292                                                 {\r
 293                                                         /* Start the next message - which was\r
 294                                                         retrieved from the queue. */\r
 295                                                         I2C_I2CONSET = i2cSTA_BIT;\r
 296                                                 }\r
 297                                                 else\r
 298                                                 {\r
 299                                                         /* No more messages were found to be waiting for\r
 300                                                         transaction so the bus is free. */\r
 301                                                         ulBusFree = ( unsigned long ) pdTRUE;                   \r
 302                                                 }                                               \r
 303                                         }\r
 304                                         else\r
 305                                         {\r
 306                                                 /* There are more bytes to receive but don't ack the \r
 307                                                 last byte. */\r
 308                                                 if( lBytesLeft <= i2cJUST_ONE_BYTE_TO_RX )\r
 309                                                 {\r
 310                                                         I2C_I2CONCLR = i2cAA_BIT;\r
 311                                                 }                                                        \r
 312                                         }\r
 313                                 }\r
 314                                 else\r
 315                                 {\r
 316                                         /* Something unexpected happened - give up. */\r
 317                                         i2cEND_TRANSMISSION( pdFAIL );                                  \r
 318                                 }\r
 319 \r
 320                                 break;\r
 321                                 \r
 322                 case eSentData  :       \r
 323 \r
 324                                 /* We sent a data byte, if successful send the  next byte in \r
 325                                 the message. */\r
 326                                 if( I2C_I2STAT == i2cSTATUS_DATA_TXED )\r
 327                                 {\r
 328                                         /* Index to the next byte to send. */\r
 329                                         lMessageIndex++;\r
 330                                         if( lMessageIndex < 0 )\r
 331                                         {\r
 332                                                 /* lMessage index is still negative so we have so far \r
 333                                                 only sent the first byte of the buffer address.  Send \r
 334                                                 the second byte now, then initialise the buffer index\r
 335                                                 to zero so the next byte sent comes from the actual \r
 336                                                 data buffer. */\r
 337                                                 I2C_I2DAT = pxCurrentMessage->ucBufferAddressLowByte;\r
 338                                         }\r
 339                                         else if( lMessageIndex < pxCurrentMessage->lMessageLength )\r
 340                                         {\r
 341                                                 /* Simply send the next byte in the tx buffer. */\r
 342                                                 I2C_I2DAT = pxCurrentMessage->pucBuffer[ lMessageIndex ];                                                                               \r
 343                                         }\r
 344                                         else\r
 345                                         {\r
 346                                                 /* No more bytes in this message to be send.  Finished \r
 347                                                 sending message - send a stop bit. */\r
 348                                                 i2cEND_TRANSMISSION( pdPASS );\r
 349 \r
 350                                                 /* If xMessageCompleteSemaphore is not null then there\r
 351                                                 is a task waiting for this message to be sent and the\r
 352                                                 semaphore must be 'given' to wake the task. */\r
 353                                                 if( pxCurrentMessage->xMessageCompleteSemaphore )\r
 354                                                 {\r
 355                                                         xSemaphoreGiveFromISR( pxCurrentMessage->xMessageCompleteSemaphore, &xHigherPriorityTaskWoken );\r
 356                                                 }\r
 357 \r
 358                                                 /* Are there any other messages to transact? */\r
 359                                                 if( xQueueReceiveFromISR( xMessagesForTx, &pxCurrentMessage, &xHigherPriorityTaskWoken ) == pdTRUE )\r
 360                                                 {\r
 361                                                         /* Start the next message from the Tx queue. */\r
 362                                                         I2C_I2CONSET = i2cSTA_BIT;\r
 363                                                 }\r
 364                                                 else\r
 365                                                 {\r
 366                                                         /* No more message were queues for transaction so \r
 367                                                         the bus is free. */\r
 368                                                         ulBusFree = ( unsigned long ) pdTRUE;                   \r
 369                                                 }\r
 370                                         }\r
 371                                 }\r
 372                                 else\r
 373                                 {\r
 374                                         /* Something unexpected happened, give up. */\r
 375                                         i2cEND_TRANSMISSION( pdFAIL );                                  \r
 376                                 }\r
 377                                 break;\r
 378 \r
 379                 default :       \r
 380                 \r
 381                                 /* Should never get here. */\r
 382                                 eCurrentState = eSentStart;\r
 383                                 break;\r
 384         }       \r
 385 \r
 386         /* Clear the interrupt. */\r
 387         I2C_I2CONCLR = i2cSI_BIT;\r
 388         VICVectAddr = i2cCLEAR_VIC_INTERRUPT;\r
 389 \r
 390         if( xHigherPriorityTaskWoken )\r
 391         {\r
 392                 portYIELD_FROM_ISR();\r
 393         }\r
 394 }\r
 395 /*-----------------------------------------------------------*/\r
 396 \r