2 FreeRTOS V7.4.0 - Copyright (C) 2013 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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33 >>>>>>NOTE<<<<<< The modification to the GPL is included to allow you to
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34 distribute a combined work that includes FreeRTOS without being obliged to
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35 provide the source code for proprietary components outside of the FreeRTOS
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38 FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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39 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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40 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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41 details. You should have received a copy of the GNU General Public License
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42 and the FreeRTOS license exception along with FreeRTOS; if not itcan be
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43 viewed here: http://www.freertos.org/a00114.html and also obtained by
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44 writing to Real Time Engineers Ltd., contact details for whom are available
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45 on the FreeRTOS WEB site.
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49 ***************************************************************************
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51 * Having a problem? Start by reading the FAQ "My application does *
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52 * not run, what could be wrong?" *
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54 * http://www.FreeRTOS.org/FAQHelp.html *
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56 ***************************************************************************
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59 http://www.FreeRTOS.org - Documentation, books, training, latest versions,
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60 license and Real Time Engineers Ltd. contact details.
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62 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
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63 including FreeRTOS+Trace - an indispensable productivity tool, and our new
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64 fully thread aware and reentrant UDP/IP stack.
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66 http://www.OpenRTOS.com - Real Time Engineers ltd license FreeRTOS to High
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67 Integrity Systems, who sell the code with commercial support,
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68 indemnification and middleware, under the OpenRTOS brand.
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70 http://www.SafeRTOS.com - High Integrity Systems also provide a safety
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71 engineered and independently SIL3 certified version for use in safety and
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72 mission critical applications that require provable dependability.
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76 /* BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER.
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78 * This file only supports UART 1
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81 /* Standard includes. */
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84 /* Scheduler includes. */
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85 #include "FreeRTOS.h"
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89 /* Demo application includes. */
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92 /* Constants required to setup the hardware. */
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93 #define serTX_AND_RX ( ( unsigned portCHAR ) 0x03 )
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95 /* Misc. constants. */
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96 #define serNO_BLOCK ( ( portTickType ) 0 )
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98 /* Enable the UART Tx interrupt. */
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99 #define vInterruptOn() IFG2 |= UTXIFG1
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101 /* The queue used to hold received characters. */
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102 static xQueueHandle xRxedChars;
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104 /* The queue used to hold characters waiting transmission. */
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105 static xQueueHandle xCharsForTx;
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107 static volatile portSHORT sTHREEmpty;
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109 /*-----------------------------------------------------------*/
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111 xComPortHandle xSerialPortInitMinimal( unsigned portLONG ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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113 unsigned portLONG ulBaudRateCount;
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115 /* Initialise the hardware. */
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117 /* Generate the baud rate constants for the wanted baud rate. */
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118 ulBaudRateCount = configCPU_CLOCK_HZ / ulWantedBaud;
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120 portENTER_CRITICAL();
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122 /* Create the queues used by the com test task. */
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123 xRxedChars = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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124 xCharsForTx = xQueueCreate( uxQueueLength, ( unsigned portBASE_TYPE ) sizeof( signed portCHAR ) );
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129 /* Set pin function. */
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130 P4SEL |= serTX_AND_RX;
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132 /* All other bits remain at zero for n, 8, 1 interrupt driven operation.
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134 U1CTL |= CHAR + LISTEN;
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137 /* Setup baud rate low byte. */
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138 U1BR0 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );
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140 /* Setup baud rate high byte. */
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141 ulBaudRateCount >>= 8UL;
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142 U1BR1 = ( unsigned portCHAR ) ( ulBaudRateCount & ( unsigned portLONG ) 0xff );
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144 /* Enable ports. */
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145 ME2 |= UTXE1 + URXE1;
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150 /* Nothing in the buffer yet. */
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151 sTHREEmpty = pdTRUE;
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153 /* Enable interrupts. */
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154 IE2 |= URXIE1 + UTXIE1;
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156 portEXIT_CRITICAL();
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158 /* Unlike other ports, this serial code does not allow for more than one
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159 com port. We therefore don't return a pointer to a port structure and can
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160 instead just return NULL. */
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163 /*-----------------------------------------------------------*/
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165 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed portCHAR *pcRxedChar, portTickType xBlockTime )
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167 /* Get the next character from the buffer. Return false if no characters
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168 are available, or arrive before xBlockTime expires. */
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169 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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178 /*-----------------------------------------------------------*/
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180 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed portCHAR cOutChar, portTickType xBlockTime )
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182 signed portBASE_TYPE xReturn;
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184 /* Transmit a character. */
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186 portENTER_CRITICAL();
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188 if( sTHREEmpty == pdTRUE )
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190 /* If sTHREEmpty is true then the UART Tx ISR has indicated that
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191 there are no characters queued to be transmitted - so we can
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192 write the character directly to the shift Tx register. */
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193 sTHREEmpty = pdFALSE;
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194 U1TXBUF = cOutChar;
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199 /* sTHREEmpty is false, so there are still characters waiting to be
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200 transmitted. We have to queue this character so it gets
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201 transmitted in turn. */
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203 /* Return false if after the block time there is no room on the Tx
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204 queue. It is ok to block inside a critical section as each task
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205 maintains it's own critical section status. */
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206 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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208 /* Depending on queue sizing and task prioritisation: While we
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209 were blocked waiting to post on the queue interrupts were not
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210 disabled. It is possible that the serial ISR has emptied the
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211 Tx queue, in which case we need to start the Tx off again
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212 writing directly to the Tx register. */
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213 if( ( sTHREEmpty == pdTRUE ) && ( xReturn == pdPASS ) )
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215 /* Get back the character we just posted. */
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216 xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
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217 sTHREEmpty = pdFALSE;
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218 U1TXBUF = cOutChar;
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222 portEXIT_CRITICAL();
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226 /*-----------------------------------------------------------*/
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228 #if configINTERRUPT_EXAMPLE_METHOD == 1
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231 * UART RX interrupt service routine.
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233 #pragma vector=UART1RX_VECTOR
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234 __interrupt void vRxISR( void )
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236 signed portCHAR cChar;
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237 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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239 /* Get the character from the UART and post it on the queue of Rxed
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243 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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245 if( xHigherPriorityTaskWoken )
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247 /*If the post causes a task to wake force a context switch
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248 as the woken task may have a higher priority than the task we have
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253 /* Make sure any low power mode bits are clear before leaving the ISR. */
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254 __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
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256 /*-----------------------------------------------------------*/
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259 * UART Tx interrupt service routine.
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261 #pragma vector=UART1TX_VECTOR
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262 __interrupt void vTxISR( void )
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264 signed portCHAR cChar;
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265 portBASE_TYPE xTaskWoken = pdFALSE;
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267 /* The previous character has been transmitted. See if there are any
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268 further characters waiting transmission. */
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270 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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272 /* There was another character queued - transmit it now. */
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277 /* There were no other characters to transmit. */
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278 sTHREEmpty = pdTRUE;
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281 /* Make sure any low power mode bits are clear before leaving the ISR. */
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282 __bic_SR_register_on_exit( SCG1 + SCG0 + OSCOFF + CPUOFF );
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284 /*-----------------------------------------------------------*/
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286 #elif configINTERRUPT_EXAMPLE_METHOD == 2
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288 /* This is a standard C function as an assembly file wrapper is used as an
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289 interrupt entry point. */
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290 void vRxISR( void )
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292 signed portCHAR cChar;
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293 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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295 /* Get the character from the UART and post it on the queue of Rxed
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299 xQueueSendFromISR( xRxedChars, &cChar, &xHigherPriorityTaskWoken );
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301 /*If the post causes a task to wake force a context switch
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302 as the woken task may have a higher priority than the task we have
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304 portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
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306 /*-----------------------------------------------------------*/
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308 /* This is a standard C function as an assembly file wrapper is used as an
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309 interrupt entry point. */
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310 void vTxISR( void )
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312 signed portCHAR cChar;
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313 portBASE_TYPE xTaskWoken = pdFALSE;
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315 /* The previous character has been transmitted. See if there are any
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316 further characters waiting transmission. */
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318 if( xQueueReceiveFromISR( xCharsForTx, &cChar, &xTaskWoken ) == pdTRUE )
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320 /* There was another character queued - transmit it now. */
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325 /* There were no other characters to transmit. */
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326 sTHREEmpty = pdTRUE;
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330 #endif /* configINTERRUPT_EXAMPLE_METHOD */
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331 /*-----------------------------------------------------------*/
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