2 FreeRTOS V4.0.1 - Copyright (C) 2003-2006 Richard Barry.
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4 This file is part of the FreeRTOS distribution.
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6 FreeRTOS 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 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; 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, 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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36 + Call to the more efficient portSWITCH_CONTEXT() replaces the call to
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37 taskYIELD() in the ISR.
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41 + The semaphore task is not operational. This does nothing but check
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42 the semaphore from ISR functionality.
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43 + ISR modified slightly so only Rx or Tx is serviced per ISR - not both.
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45 Changes from V1.2.0:
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47 + Change so Tx uses a DMA channel, and Rx uses an interrupt.
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51 + The function xPortInitMinimal() has been renamed to
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52 xSerialPortInitMinimal() and the function xPortInit() has been renamed
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53 to xSerialPortInit().
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57 + Reverted back to the non-DMA serial port driver, with a slightly modified
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58 ISR. This is a better test of the scheduler mechanisms.
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59 + A critical section is now used in vInterruptOn().
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60 + Flag sTxInterruptOn has been added to the port structure. This allows
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61 checking of the interrupt enable status without performing any IO.
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65 + Use portTickType in place of unsigned pdLONG for delay periods.
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66 + Slightly more efficient vSerialSendString() implementation.
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67 + cQueueReieveFromISR() used in place of xQueueReceive() in ISR.
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72 #include "FreeRTOS.h"
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75 #include "portasm.h"
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78 #define serMAX_PORTS ( ( unsigned portSHORT ) 2 )
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80 #define serPORT_0_INT_REG ( 0xff44 )
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81 #define serPORT_0_BAUD_REG ( 0xff88 )
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82 #define serPORT_0_RX_REG ( 0xff86 )
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83 #define serPORT_0_TX_REG ( 0xff84 )
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84 #define serPORT_0_STATUS_REG ( 0xff82 )
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85 #define serPORT_0_CTRL_REG ( 0xff80 )
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86 #define serPORT_0_IRQ ( 0x14 )
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88 #define serPORT_1_INT_REG ( 0xff42 )
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89 #define serPORT_1_BAUD_REG ( 0xff18 )
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90 #define serPORT_1_RX_REG ( 0xff16 )
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91 #define serPORT_1_TX_REG ( 0xff14 )
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92 #define serPORT_1_STATUS_REG ( 0xff12 )
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93 #define serPORT_1_CTRL_REG ( 0xff10 )
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94 #define serPORT_1_IRQ ( 0x11 )
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96 #define serTX_EMPTY ( ( unsigned portSHORT ) 0x40 )
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97 #define serRX_READY ( ( unsigned portSHORT ) 0x80 )
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99 #define serRESET_PIC( usEOI_TYPE ) portOUTPUT_WORD( ( unsigned portSHORT ) 0xff22, usEOI_TYPE )
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100 #define serTX_HOLD_EMPTY_INT ( ( unsigned portSHORT ) 0x100 )
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102 #define serENABLE_INTERRUPTS ( ( unsigned portSHORT ) 0x80 )
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103 #define serMODE ( ( unsigned portSHORT ) 0x01 )
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104 #define serENABLE_TX_MACHINES ( ( unsigned portSHORT ) 0x40 )
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105 #define serENABLE_RX_MACHINES ( ( unsigned portSHORT ) 0x20 )
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106 #define serINTERRUPT_MASK ( ( unsigned portSHORT ) 0x08 )
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107 #define serCLEAR_ALL_STATUS_BITS ( ( unsigned portSHORT ) 0x00 )
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108 #define serINTERRUPT_PRIORITY ( ( unsigned portSHORT ) 0x01 ) /*< Just below the scheduler priority. */
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110 #define serDONT_BLOCK ( ( portTickType ) 0 )
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168 /* Must be same order as eBaud definitions. */
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169 static const unsigned portSHORT usBaudRateDivisor[] =
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171 0, /* Not sure if the first 6 are correct. First cannot be used. */
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191 typedef struct xCOM_PORT
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193 /* Hardware parameters for this port. */
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194 portSHORT sTxInterruptOn;
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195 unsigned portSHORT usIntReg;
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196 unsigned portSHORT usBaudReg;
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197 unsigned portSHORT usRxReg;
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198 unsigned portSHORT usTxReg;
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199 unsigned portSHORT usStatusReg;
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200 unsigned portSHORT usCtrlReg;
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202 unsigned portSHORT usIRQVector;
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204 /* Queues used for communications with com test task. */
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205 xQueueHandle xRxedChars;
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206 xQueueHandle xCharsForTx;
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208 /* This semaphore does nothing useful except test a feature of the
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210 xSemaphoreHandle xTestSem;
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214 static xComPort xPorts[ serMAX_PORTS ] =
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216 { 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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217 { 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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220 typedef xComPort * xComPortHandle;
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222 /* These prototypes are repeated here so we don't have to include the serial header. This allows
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223 the xComPortHandle structure details to be private to this file. */
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224 xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned portBASE_TYPE uxBufferLength );
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225 portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, portCHAR *pcRxedChar, portTickType xBlockTime );
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226 portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, portCHAR cOutChar, portTickType xBlockTime );
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227 void vSerialClose( xComPortHandle xPort );
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228 portSHORT sSerialWaitForSemaphore( xComPortHandle xPort );
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229 /*-----------------------------------------------------------*/
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231 static portSHORT xComPortISR( xComPort * const pxPort );
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233 #define vInterruptOn( pxPort, usInterrupt ) \
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235 unsigned portSHORT usIn; \
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237 portENTER_CRITICAL(); \
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239 if( pxPort->sTxInterruptOn == pdFALSE ) \
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241 usIn = portINPUT_WORD( pxPort->usCtrlReg ); \
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242 portOUTPUT_WORD( pxPort->usCtrlReg, usIn | usInterrupt ); \
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244 pxPort->sTxInterruptOn = pdTRUE; \
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247 portEXIT_CRITICAL(); \
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249 /*-----------------------------------------------------------*/
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251 #define vInterruptOff( pxPort, usInterrupt ) \
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253 unsigned portSHORT usIn = portINPUT_WORD( pxPort->usCtrlReg ); \
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254 if( usIn & usInterrupt ) \
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256 portOUTPUT_WORD( pxPort->usCtrlReg, usIn & ~usInterrupt); \
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257 pxPort->sTxInterruptOn = pdFALSE; \
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260 /*-----------------------------------------------------------*/
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263 /* Define an interrupt handler for each port */
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264 #define COM_IRQ_WRAPPER(N) \
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265 static void __interrupt COM_IRQ##N##_WRAPPER( void ) \
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267 if( xComPortISR( &( xPorts[##N##] ) ) ) \
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269 portSWITCH_CONTEXT(); \
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275 COM_IRQ_WRAPPER( 0 )
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276 COM_IRQ_WRAPPER( 1 )
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278 static pxISR xISRs[ serMAX_PORTS ] =
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284 /*-----------------------------------------------------------*/
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286 xComPortHandle xSerialPortInit( eCOMPort ePort, eBaud eWantedBaud, eParity eWantedParity, eDataBits eWantedDataBits, eStopBits eWantedStopBits, unsigned portBASE_TYPE uxBufferLength )
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288 unsigned portSHORT usPort;
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289 xComPortHandle pxPort = NULL;
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291 /* BAUDDIV = ( Microprocessor Clock / Baud Rate ) / 16 */
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293 /* Only n, 8, 1 is supported so these parameters are not required for this
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295 ( void ) eWantedParity;
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296 ( void ) eWantedDataBits;
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297 ( void ) eWantedStopBits;
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299 /* Currently only n,8,1 is supported. */
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301 usPort = ( unsigned portSHORT ) ePort;
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303 if( usPort < serMAX_PORTS )
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305 pxPort = &( xPorts[ usPort ] );
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307 portENTER_CRITICAL();
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309 unsigned portSHORT usInWord;
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311 /* Create the queues used by the com test task. */
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312 pxPort->xRxedChars = xQueueCreate( uxBufferLength, ( unsigned portBASE_TYPE ) sizeof( portCHAR ) );
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313 pxPort->xCharsForTx = xQueueCreate( uxBufferLength, ( unsigned portBASE_TYPE ) sizeof( portCHAR ) );
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315 /* Create the test semaphore. This does nothing useful except test a feature of the scheduler. */
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316 vSemaphoreCreateBinary( pxPort->xTestSem );
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318 /* There is no ISR here already to restore later. */
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319 _dos_setvect( ( portSHORT ) pxPort->usIRQVector, xISRs[ usPort ] );
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321 usInWord = portINPUT_WORD( pxPort->usIntReg );
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322 usInWord &= ~serINTERRUPT_MASK;
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323 usInWord |= serINTERRUPT_PRIORITY;
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324 portOUTPUT_WORD( pxPort->usIntReg, usInWord );
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326 portOUTPUT_WORD( pxPort->usBaudReg, usBaudRateDivisor[ eWantedBaud ] );
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327 portOUTPUT_WORD( pxPort->usCtrlReg, serENABLE_INTERRUPTS | serMODE | serENABLE_TX_MACHINES | serENABLE_RX_MACHINES );
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329 portOUTPUT_WORD( pxPort->usStatusReg, serCLEAR_ALL_STATUS_BITS );
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331 portEXIT_CRITICAL();
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335 } /*lint !e715 Some parameters are not used as only a subset of the serial port functionality is currently implemented. */
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336 /*-----------------------------------------------------------*/
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338 void vSerialPutString( xComPortHandle pxPort, const portCHAR * const pcString, unsigned portSHORT usStringLength )
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340 unsigned portSHORT usByte;
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341 portCHAR *pcNextChar;
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343 pcNextChar = ( portCHAR * ) pcString;
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345 for( usByte = 0; usByte < usStringLength; usByte++ )
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347 xQueueSend( pxPort->xCharsForTx, pcNextChar, serDONT_BLOCK );
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351 vInterruptOn( pxPort, serTX_HOLD_EMPTY_INT );
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353 /*-----------------------------------------------------------*/
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355 portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, portCHAR *pcRxedChar, portTickType xBlockTime )
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357 /* Get the next character from the buffer, note that this routine is only
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358 called having checked that the is (at least) one to get */
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359 if( xQueueReceive( pxPort->xRxedChars, pcRxedChar, xBlockTime ) )
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368 /*-----------------------------------------------------------*/
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370 portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, portCHAR cOutChar, portTickType xBlockTime )
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372 if( xQueueSend( pxPort->xCharsForTx, &cOutChar, xBlockTime ) != pdPASS )
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377 vInterruptOn( pxPort, serTX_HOLD_EMPTY_INT );
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381 /*-----------------------------------------------------------*/
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383 portBASE_TYPE xSerialWaitForSemaphore( xComPortHandle xPort )
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385 const portTickType xBlockTime = ( portTickType ) 0xffff;
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387 /* This function does nothing interesting, but test the
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388 semaphore from ISR mechanism. */
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389 return xSemaphoreTake( xPort->xTestSem, xBlockTime );
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391 /*-----------------------------------------------------------*/
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393 void vSerialClose( xComPortHandle xPort )
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395 unsigned portSHORT usOutput;
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397 /* Turn off the interrupts. We may also want to delete the queues and/or
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398 re-install the original ISR. */
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400 portENTER_CRITICAL();
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402 usOutput = portINPUT_WORD( xPort->usCtrlReg );
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404 usOutput &= ~serENABLE_INTERRUPTS;
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405 usOutput &= ~serENABLE_TX_MACHINES;
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406 usOutput &= ~serENABLE_RX_MACHINES;
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407 portOUTPUT_WORD( xPort->usCtrlReg, usOutput );
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409 usOutput = portINPUT_WORD( xPort->usIntReg );
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410 usOutput |= serINTERRUPT_MASK;
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411 portOUTPUT_WORD( xPort->usIntReg, usOutput );
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413 portEXIT_CRITICAL();
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415 /*-----------------------------------------------------------*/
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417 static portBASE_TYPE xComPortISR( xComPort * const pxPort )
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419 unsigned portSHORT usStatusRegister;
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421 portBASE_TYPE xTaskWokenByPost = pdFALSE, xAnotherTaskWokenByPost = pdFALSE, xTaskWokenByTx = pdFALSE, xContinue = pdTRUE;
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423 /* NOTE: THIS IS NOT AN EFFICIENT ISR AS IT IS DESIGNED SOLELY TO TEST
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424 THE SCHEDULER FUNCTIONALITY. REAL APPLICATIONS SHOULD NOT USE THIS
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428 while( xContinue == pdTRUE )
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430 xContinue = pdFALSE;
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431 usStatusRegister = portINPUT_WORD( pxPort->usStatusReg );
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433 if( usStatusRegister & serRX_READY )
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435 cChar = ( portCHAR ) portINPUT_WORD( pxPort->usRxReg );
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436 xTaskWokenByPost = xQueueSendFromISR( pxPort->xRxedChars, &cChar, xTaskWokenByPost );
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438 /* Also release the semaphore - this does nothing interesting and is just a test. */
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439 xAnotherTaskWokenByPost = xSemaphoreGiveFromISR( pxPort->xTestSem, xAnotherTaskWokenByPost );
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441 /* We have performed an action this cycle - there may be other to perform. */
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442 xContinue = pdTRUE;
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445 if( pxPort->sTxInterruptOn && ( usStatusRegister & serTX_EMPTY ) )
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447 if( xQueueReceiveFromISR( pxPort->xCharsForTx, &cChar, &xTaskWokenByTx ) == pdTRUE )
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449 portOUTPUT_WORD( pxPort->usTxReg, ( unsigned portSHORT ) cChar );
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451 /* We have performed an action this cycle - there may be others to perform. */
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452 xContinue = pdTRUE;
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456 /* Queue empty, nothing to send */
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457 vInterruptOff( pxPort, serTX_HOLD_EMPTY_INT );
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462 serRESET_PIC( pxPort->usIRQVector );
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464 /* If posting to the queue woke a task that was blocked on the queue we may
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465 want to switch to the woken task - depending on its priority relative to
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466 the task interrupted by this ISR. */
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467 if( xTaskWokenByPost || xAnotherTaskWokenByPost || xTaskWokenByTx)
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