git.sur5r.net Git - freertos/blob - Demo/AVR_ATMega323_IAR/serial/serial.c

   1 /*\r
   2         FreeRTOS.org V4.8.0 - Copyright (C) 2003-2008 Richard Barry.\r
   3 \r
   4         This file is part of the FreeRTOS.org distribution.\r
   5 \r
   6         FreeRTOS.org is free software; you can redistribute it and/or modify\r
   7         it under the terms of the GNU General Public License as published by\r
   8         the Free Software Foundation; either version 2 of the License, or\r
   9         (at your option) any later version.\r
  10 \r
  11         FreeRTOS.org is distributed in the hope that it will be useful,\r
  12         but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  13         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  14         GNU General Public License for more details.\r
  15 \r
  16         You should have received a copy of the GNU General Public License\r
  17         along with FreeRTOS.org; if not, write to the Free Software\r
  18         Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA\r
  19 \r
  20         A special exception to the GPL can be applied should you wish to distribute\r
  21         a combined work that includes FreeRTOS.org, without being obliged to provide\r
  22         the source code for any proprietary components.  See the licensing section \r
  23         of http://www.FreeRTOS.org for full details of how and when the exception\r
  24         can be applied.\r
  25 \r
  26         ***************************************************************************\r
  27         ***************************************************************************\r
  28         *                                                                                                                                                 *\r
  29         * SAVE TIME AND MONEY!  Why not get us to quote to get FreeRTOS.org               *\r
  30         * running on your hardware - or even write all or part of your application*\r
  31         * for you?  See http://www.OpenRTOS.com for details.                                      *\r
  32         *                                                                                                                                                 *\r
  33         ***************************************************************************\r
  34         ***************************************************************************\r
  35 \r
  36         Please ensure to read the configuration and relevant port sections of the\r
  37         online documentation.\r
  38 \r
  39         http://www.FreeRTOS.org - Documentation, latest information, license and \r
  40         contact details.\r
  41 \r
  42         http://www.SafeRTOS.com - A version that is certified for use in safety \r
  43         critical systems.\r
  44 \r
  45         http://www.OpenRTOS.com - Commercial support, development, porting, \r
  46         licensing and training services.\r
  47 */\r
  48 \r
  49 \r
  50 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR IAR AVR PORT. */\r
  51 \r
  52 \r
  53 #include <stdlib.h>\r
  54 #include "FreeRTOS.h"\r
  55 #include "queue.h"\r
  56 #include "task.h"\r
  57 #include "serial.h"\r
  58 \r
  59 #define serBAUD_DIV_CONSTANT                    ( ( unsigned portLONG ) 16 )\r
  60 \r
  61 /* Constants for writing to UCSRB. */\r
  62 #define serRX_INT_ENABLE                                ( ( unsigned portCHAR ) 0x80 )\r
  63 #define serRX_ENABLE                                    ( ( unsigned portCHAR ) 0x10 )\r
  64 #define serTX_ENABLE                                    ( ( unsigned portCHAR ) 0x08 )\r
  65 #define serTX_INT_ENABLE                                ( ( unsigned portCHAR ) 0x20 )\r
  66 \r
  67 /* Constants for writing to UCSRC. */\r
  68 #define serUCSRC_SELECT                                 ( ( unsigned portCHAR ) 0x80 )\r
  69 #define serEIGHT_DATA_BITS                              ( ( unsigned portCHAR ) 0x06 )\r
  70 \r
  71 static xQueueHandle xRxedChars; \r
  72 static xQueueHandle xCharsForTx; \r
  73 \r
  74 #define vInterruptOn()                                                                          \\r
  75 {                                                                                                                       \\r
  76         unsigned portCHAR ucByte;                                                               \\r
  77                                                                                                                         \\r
  78         ucByte = UCSRB;                                                                                 \\r
  79         ucByte |= serTX_INT_ENABLE;                                                             \\r
  80         outb( UCSRB, ucByte );                                                                  \\r
  81 }                                                                                                                                                               \r
  82 /*-----------------------------------------------------------*/\r
  83 \r
  84 #define vInterruptOff()                                                                         \\r
  85 {                                                                                                                       \\r
  86         unsigned portCHAR ucByte;                                                               \\r
  87                                                                                                                         \\r
  88         ucByte = UCSRB;                                                                                 \\r
  89         ucByte &= ~serTX_INT_ENABLE;                                                    \\r
  90         outb( UCSRB, ucByte );                                                                  \\r
  91 }\r
  92 /*-----------------------------------------------------------*/\r
  93 \r
  94 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )\r
  95 {\r
  96 unsigned portLONG ulBaudRateCounter;\r
  97 unsigned portCHAR ucByte;\r
  98 \r
  99         portENTER_CRITICAL();\r
 100         {\r
 101                 /* Create the queues used by the com test task. */\r
 102                 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );\r
 103                 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );\r
 104 \r
 105                 /* Calculate the baud rate register value from the equation in the\r
 106                 data sheet. */\r
 107                 ulBaudRateCounter = ( configCPU_CLOCK_HZ / ( serBAUD_DIV_CONSTANT * ulWantedBaud ) ) - ( unsigned portLONG ) 1;\r
 108 \r
 109                 /* Set the baud rate. */        \r
 110                 ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );      \r
 111                 outb( UBRRL, ucByte );\r
 112 \r
 113                 ulBaudRateCounter >>= ( unsigned portLONG ) 8;\r
 114                 ucByte = ( unsigned portCHAR ) ( ulBaudRateCounter & ( unsigned portLONG ) 0xff );      \r
 115                 outb( UBRRH, ucByte );\r
 116 \r
 117                 /* Enable the Rx interrupt.  The Tx interrupt will get enabled\r
 118                 later. Also enable the Rx and Tx. */\r
 119                 outb( UCSRB, serRX_INT_ENABLE | serRX_ENABLE | serTX_ENABLE );\r
 120 \r
 121                 /* Set the data bits to 8. */\r
 122                 outb( UCSRC, serUCSRC_SELECT | serEIGHT_DATA_BITS );\r
 123         }\r
 124         portEXIT_CRITICAL();\r
 125         \r
 126         /* Unlike other ports, this serial code does not allow for more than one\r
 127         com port.  We therefore don't return a pointer to a port structure and can\r
 128         instead just return NULL. */\r
 129         return NULL;\r
 130 }\r
 131 /*-----------------------------------------------------------*/\r
 132 \r
 133 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )\r
 134 {\r
 135         /* Get the next character from the buffer.  Return false if no characters\r
 136         are available, or arrive before xBlockTime expires. */\r
 137         if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )\r
 138         {\r
 139                 return pdTRUE;\r
 140         }\r
 141         else\r
 142         {\r
 143                 return pdFALSE;\r
 144         }\r
 145 }\r
 146 /*-----------------------------------------------------------*/\r
 147 \r
 148 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )\r
 149 {\r
 150         /* Return false if after the block time there is no room on the Tx queue. */\r
 151         if( xQueueSend( xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )\r
 152         {\r
 153                 return pdFAIL;\r
 154         }\r
 155 \r
 156         vInterruptOn();\r
 157 \r
 158         return pdPASS;\r
 159 }\r
 160 /*-----------------------------------------------------------*/\r
 161 \r
 162 void vSerialClose( xComPortHandle xPort )\r
 163 {\r
 164 unsigned portCHAR ucByte;\r
 165 \r
 166         /* Turn off the interrupts.  We may also want to delete the queues and/or\r
 167         re-install the original ISR. */\r
 168 \r
 169         portENTER_CRITICAL();\r
 170         {\r
 171                 vInterruptOff();\r
 172                 ucByte = UCSRB;\r
 173                 ucByte &= ~serRX_INT_ENABLE;\r
 174                 outb( UCSRB, ucByte );\r
 175         }\r
 176         portEXIT_CRITICAL();\r
 177 }\r
 178 /*-----------------------------------------------------------*/\r
 179 \r
 180 __interrupt void SIG_UART_RECV( void )\r
 181 {\r
 182 signed portCHAR cChar;\r
 183 \r
 184         /* Get the character and post it on the queue of Rxed characters.\r
 185         If the post causes a task to wake force a context switch as the woken task\r
 186         may have a higher priority than the task we have interrupted. */\r
 187         cChar = UDR;\r
 188 \r
 189         if( xQueueSendFromISR( xRxedChars, &cChar, pdFALSE ) )\r
 190         {\r
 191                 taskYIELD();\r
 192         }\r
 193 }\r
 194 /*-----------------------------------------------------------*/\r
 195 \r
 196 __interrupt void SIG_UART_DATA( void )\r
 197 {\r
 198 signed portCHAR cChar, cTaskWoken;\r
 199 \r
 200         if( xQueueReceiveFromISR( xCharsForTx, &cChar, &cTaskWoken ) == pdTRUE )\r
 201         {\r
 202                 /* Send the next character queued for Tx. */\r
 203                 outb( UDR, cChar );\r
 204         }\r
 205         else\r
 206         {\r
 207                 /* Queue empty, nothing to send. */\r
 208                 vInterruptOff();\r
 209         }\r
 210 }\r
 211 \r