2 FreeRTOS V7.3.0 - Copyright (C) 2012 Real Time Engineers Ltd.
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4 FEATURES AND PORTS ARE ADDED TO FREERTOS ALL THE TIME. PLEASE VISIT
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5 http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
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7 ***************************************************************************
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9 * FreeRTOS tutorial books are available in pdf and paperback. *
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10 * Complete, revised, and edited pdf reference manuals are also *
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13 * Purchasing FreeRTOS documentation will not only help you, by *
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14 * ensuring you get running as quickly as possible and with an *
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15 * in-depth knowledge of how to use FreeRTOS, it will also help *
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16 * the FreeRTOS project to continue with its mission of providing *
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17 * professional grade, cross platform, de facto standard solutions *
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18 * for microcontrollers - completely free of charge! *
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20 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
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22 * Thank you for using FreeRTOS, and thank you for your support! *
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24 ***************************************************************************
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27 This file is part of the FreeRTOS distribution.
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29 FreeRTOS is free software; you can redistribute it and/or modify it under
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30 the terms of the GNU General Public License (version 2) as published by the
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31 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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32 >>>NOTE<<< The modification to the GPL is included to allow you to
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33 distribute a combined work that includes FreeRTOS without being obliged to
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34 provide the source code for proprietary components outside of the FreeRTOS
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35 kernel. FreeRTOS is distributed in the hope that it will be useful, but
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36 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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37 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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38 more details. You should have received a copy of the GNU General Public
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39 License and the FreeRTOS license exception along with FreeRTOS; if not it
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40 can be viewed here: http://www.freertos.org/a00114.html and also obtained
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41 by writing to Richard Barry, contact details for whom are available on the
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46 ***************************************************************************
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48 * Having a problem? Start by reading the FAQ "My application does *
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49 * not run, what could be wrong?" *
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51 * http://www.FreeRTOS.org/FAQHelp.html *
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53 ***************************************************************************
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56 http://www.FreeRTOS.org - Documentation, training, latest versions, license
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57 and contact details.
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59 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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60 including FreeRTOS+Trace - an indispensable productivity tool.
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62 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
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63 the code with commercial support, indemnification, and middleware, under
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64 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
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65 provide a safety engineered and independently SIL3 certified version under
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66 the SafeRTOS brand: http://www.SafeRTOS.com.
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72 + Call to the more efficient portSWITCH_CONTEXT() replaces the call to
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73 taskYIELD() in the ISR.
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77 + The semaphore task is not operational. This does nothing but check
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78 the semaphore from ISR functionality.
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79 + ISR modified slightly so only Rx or Tx is serviced per ISR - not both.
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81 Changes from V1.2.0:
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83 + Change so Tx uses a DMA channel, and Rx uses an interrupt.
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87 + The function xPortInitMinimal() has been renamed to
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88 xSerialPortInitMinimal() and the function xPortInit() has been renamed
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89 to xSerialPortInit().
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93 + Reverted back to the non-DMA serial port driver, with a slightly modified
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94 ISR. This is a better test of the scheduler mechanisms.
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95 + A critical section is now used in vInterruptOn().
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96 + Flag sTxInterruptOn has been added to the port structure. This allows
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97 checking of the interrupt enable status without performing any IO.
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101 + Use portTickType in place of unsigned pdLONG for delay periods.
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102 + Slightly more efficient vSerialSendString() implementation.
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103 + cQueueReieveFromISR() used in place of xQueueReceive() in ISR.
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106 #include <stdlib.h>
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108 #include "FreeRTOS.h"
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111 #include "portasm.h"
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112 #include "semphr.h"
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114 #define serMAX_PORTS ( ( unsigned short ) 2 )
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116 #define serPORT_0_INT_REG ( 0xff44 )
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117 #define serPORT_0_BAUD_REG ( 0xff88 )
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118 #define serPORT_0_RX_REG ( 0xff86 )
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119 #define serPORT_0_TX_REG ( 0xff84 )
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120 #define serPORT_0_STATUS_REG ( 0xff82 )
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121 #define serPORT_0_CTRL_REG ( 0xff80 )
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122 #define serPORT_0_IRQ ( 0x14 )
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124 #define serPORT_1_INT_REG ( 0xff42 )
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125 #define serPORT_1_BAUD_REG ( 0xff18 )
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126 #define serPORT_1_RX_REG ( 0xff16 )
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127 #define serPORT_1_TX_REG ( 0xff14 )
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128 #define serPORT_1_STATUS_REG ( 0xff12 )
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129 #define serPORT_1_CTRL_REG ( 0xff10 )
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130 #define serPORT_1_IRQ ( 0x11 )
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132 #define serTX_EMPTY ( ( unsigned short ) 0x40 )
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133 #define serRX_READY ( ( unsigned short ) 0x80 )
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135 #define serRESET_PIC( usEOI_TYPE ) portOUTPUT_WORD( ( unsigned short ) 0xff22, usEOI_TYPE )
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136 #define serTX_HOLD_EMPTY_INT ( ( unsigned short ) 0x100 )
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138 #define serENABLE_INTERRUPTS ( ( unsigned short ) 0x80 )
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139 #define serMODE ( ( unsigned short ) 0x01 )
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140 #define serENABLE_TX_MACHINES ( ( unsigned short ) 0x40 )
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141 #define serENABLE_RX_MACHINES ( ( unsigned short ) 0x20 )
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142 #define serINTERRUPT_MASK ( ( unsigned short ) 0x08 )
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143 #define serCLEAR_ALL_STATUS_BITS ( ( unsigned short ) 0x00 )
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144 #define serINTERRUPT_PRIORITY ( ( unsigned short ) 0x01 ) /*< Just below the scheduler priority. */
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146 #define serDONT_BLOCK ( ( portTickType ) 0 )
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204 /* Must be same order as eBaud definitions. */
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205 static const unsigned short usBaudRateDivisor[] =
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207 0, /* Not sure if the first 6 are correct. First cannot be used. */
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227 typedef struct xCOM_PORT
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229 /* Hardware parameters for this port. */
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230 short sTxInterruptOn;
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231 unsigned short usIntReg;
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232 unsigned short usBaudReg;
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233 unsigned short usRxReg;
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234 unsigned short usTxReg;
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235 unsigned short usStatusReg;
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236 unsigned short usCtrlReg;
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238 unsigned short usIRQVector;
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240 /* Queues used for communications with com test task. */
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241 xQueueHandle xRxedChars;
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242 xQueueHandle xCharsForTx;
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244 /* This semaphore does nothing useful except test a feature of the
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246 xSemaphoreHandle xTestSem;
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250 static xComPort xPorts[ serMAX_PORTS ] =
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252 { pdFALSE, serPORT_0_INT_REG, serPORT_0_BAUD_REG, serPORT_0_RX_REG, serPORT_0_TX_REG, serPORT_0_STATUS_REG, serPORT_0_CTRL_REG, serPORT_0_IRQ, NULL, NULL, NULL },
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253 { pdFALSE, serPORT_1_INT_REG, serPORT_1_BAUD_REG, serPORT_1_RX_REG, serPORT_1_TX_REG, serPORT_1_STATUS_REG, serPORT_1_CTRL_REG, serPORT_1_IRQ, NULL, NULL, NULL }
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256 typedef xComPort * xComPortHandle;
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258 /* These prototypes are repeated here so we don't have to include the serial header. This allows
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259 the xComPortHandle structure details to be private to this file. */
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260 xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned portBASE_TYPE uxBufferLength );
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261 portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, char *pcRxedChar, portTickType xBlockTime );
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262 portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, char cOutChar, portTickType xBlockTime );
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263 void vSerialClose( xComPortHandle xPort );
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264 short sSerialWaitForSemaphore( xComPortHandle xPort );
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265 /*-----------------------------------------------------------*/
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267 static short xComPortISR( xComPort * const pxPort );
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269 #define vInterruptOn( pxPort, usInterrupt ) \
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271 unsigned short usIn; \
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273 portENTER_CRITICAL(); \
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275 if( pxPort->sTxInterruptOn == pdFALSE ) \
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277 usIn = portINPUT_WORD( pxPort->usCtrlReg ); \
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278 portOUTPUT_WORD( pxPort->usCtrlReg, usIn | usInterrupt ); \
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280 pxPort->sTxInterruptOn = pdTRUE; \
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283 portEXIT_CRITICAL(); \
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285 /*-----------------------------------------------------------*/
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287 #define vInterruptOff( pxPort, usInterrupt ) \
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289 unsigned short usIn = portINPUT_WORD( pxPort->usCtrlReg ); \
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290 if( usIn & usInterrupt ) \
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292 portOUTPUT_WORD( pxPort->usCtrlReg, usIn & ~usInterrupt); \
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293 pxPort->sTxInterruptOn = pdFALSE; \
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296 /*-----------------------------------------------------------*/
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299 /* Define an interrupt handler for each port */
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300 #define COM_IRQ_WRAPPER(N) \
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301 static void __interrupt COM_IRQ##N##_WRAPPER( void ) \
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303 if( xComPortISR( &( xPorts[##N##] ) ) ) \
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305 portSWITCH_CONTEXT(); \
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311 COM_IRQ_WRAPPER( 0 )
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312 COM_IRQ_WRAPPER( 1 )
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314 static pxISR xISRs[ serMAX_PORTS ] =
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320 /*-----------------------------------------------------------*/
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322 xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned portBASE_TYPE uxBufferLength )
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324 unsigned short usPort;
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325 xComPortHandle pxPort = NULL;
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327 /* BAUDDIV = ( Microprocessor Clock / Baud Rate ) / 16 */
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329 /* Only n, 8, 1 is supported so these parameters are not required for this
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331 ( void ) eWantedParity;
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332 ( void ) eWantedDataBits;
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333 ( void ) eWantedStopBits;
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335 /* Currently only n,8,1 is supported. */
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337 usPort = ( unsigned short ) ePort;
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339 if( usPort < serMAX_PORTS )
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341 pxPort = &( xPorts[ usPort ] );
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343 portENTER_CRITICAL();
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345 unsigned short usInWord;
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347 /* Create the queues used by the com test task. */
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348 pxPort->xRxedChars = xQueueCreate( uxBufferLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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349 pxPort->xCharsForTx = xQueueCreate( uxBufferLength, ( unsigned portBASE_TYPE ) sizeof( char ) );
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351 /* Create the test semaphore. This does nothing useful except test a feature of the scheduler. */
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352 vSemaphoreCreateBinary( pxPort->xTestSem );
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354 /* There is no ISR here already to restore later. */
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355 _dos_setvect( ( short ) pxPort->usIRQVector, xISRs[ usPort ] );
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357 usInWord = portINPUT_WORD( pxPort->usIntReg );
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358 usInWord &= ~serINTERRUPT_MASK;
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359 usInWord |= serINTERRUPT_PRIORITY;
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360 portOUTPUT_WORD( pxPort->usIntReg, usInWord );
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362 portOUTPUT_WORD( pxPort->usBaudReg, usBaudRateDivisor[ eWantedBaud ] );
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363 portOUTPUT_WORD( pxPort->usCtrlReg, serENABLE_INTERRUPTS | serMODE | serENABLE_TX_MACHINES | serENABLE_RX_MACHINES );
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365 portOUTPUT_WORD( pxPort->usStatusReg, serCLEAR_ALL_STATUS_BITS );
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367 portEXIT_CRITICAL();
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371 } /*lint !e715 Some parameters are not used as only a subset of the serial port functionality is currently implemented. */
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372 /*-----------------------------------------------------------*/
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374 void vSerialPutString( xComPortHandle pxPort, const char * const pcString, unsigned short usStringLength )
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376 unsigned short usByte;
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379 pcNextChar = ( char * ) pcString;
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381 for( usByte = 0; usByte < usStringLength; usByte++ )
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383 xQueueSend( pxPort->xCharsForTx, pcNextChar, serDONT_BLOCK );
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387 vInterruptOn( pxPort, serTX_HOLD_EMPTY_INT );
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389 /*-----------------------------------------------------------*/
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391 portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, char *pcRxedChar, portTickType xBlockTime )
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393 /* Get the next character from the buffer, note that this routine is only
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394 called having checked that the is (at least) one to get */
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395 if( xQueueReceive( pxPort->xRxedChars, pcRxedChar, xBlockTime ) )
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404 /*-----------------------------------------------------------*/
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406 portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, char cOutChar, portTickType xBlockTime )
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408 if( xQueueSend( pxPort->xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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413 vInterruptOn( pxPort, serTX_HOLD_EMPTY_INT );
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417 /*-----------------------------------------------------------*/
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419 portBASE_TYPE xSerialWaitForSemaphore( xComPortHandle xPort )
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421 const portTickType xBlockTime = ( portTickType ) 0xffff;
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423 /* This function does nothing interesting, but test the
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424 semaphore from ISR mechanism. */
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425 return xSemaphoreTake( xPort->xTestSem, xBlockTime );
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427 /*-----------------------------------------------------------*/
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429 void vSerialClose( xComPortHandle xPort )
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431 unsigned short usOutput;
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433 /* Turn off the interrupts. We may also want to delete the queues and/or
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434 re-install the original ISR. */
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436 portENTER_CRITICAL();
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438 usOutput = portINPUT_WORD( xPort->usCtrlReg );
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440 usOutput &= ~serENABLE_INTERRUPTS;
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441 usOutput &= ~serENABLE_TX_MACHINES;
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442 usOutput &= ~serENABLE_RX_MACHINES;
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443 portOUTPUT_WORD( xPort->usCtrlReg, usOutput );
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445 usOutput = portINPUT_WORD( xPort->usIntReg );
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446 usOutput |= serINTERRUPT_MASK;
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447 portOUTPUT_WORD( xPort->usIntReg, usOutput );
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449 portEXIT_CRITICAL();
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451 /*-----------------------------------------------------------*/
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453 static portBASE_TYPE xComPortISR( xComPort * const pxPort )
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455 unsigned short usStatusRegister;
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457 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE, xContinue = pdTRUE;
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459 /* NOTE: THIS IS NOT AN EFFICIENT ISR AS IT IS DESIGNED SOLELY TO TEST
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460 THE SCHEDULER FUNCTIONALITY. REAL APPLICATIONS SHOULD NOT USE THIS
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464 while( xContinue == pdTRUE )
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466 xContinue = pdFALSE;
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467 usStatusRegister = portINPUT_WORD( pxPort->usStatusReg );
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469 if( usStatusRegister & serRX_READY )
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471 cChar = ( char ) portINPUT_WORD( pxPort->usRxReg );
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472 xQueueSendFromISR( pxPort->xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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474 /* Also release the semaphore - this does nothing interesting and is just a test. */
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475 xSemaphoreGiveFromISR( pxPort->xTestSem, &xHigherPriorityTaskWoken );
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477 /* We have performed an action this cycle - there may be other to perform. */
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478 xContinue = pdTRUE;
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481 if( pxPort->sTxInterruptOn && ( usStatusRegister & serTX_EMPTY ) )
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483 if( xQueueReceiveFromISR( pxPort->xCharsForTx, &cChar, &xHigherPriorityTaskWoken ) == pdTRUE )
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485 portOUTPUT_WORD( pxPort->usTxReg, ( unsigned short ) cChar );
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487 /* We have performed an action this cycle - there may be others to perform. */
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488 xContinue = pdTRUE;
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492 /* Queue empty, nothing to send */
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493 vInterruptOff( pxPort, serTX_HOLD_EMPTY_INT );
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498 serRESET_PIC( pxPort->usIRQVector );
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500 /* If posting to the queue woke a task that was blocked on the queue we may
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501 want to switch to the woken task - depending on its priority relative to
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502 the task interrupted by this ISR. */
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503 return xHigherPriorityTaskWoken;
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