2 FreeRTOS V7.4.1 - 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 it can 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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78 + Made serial ISR handling more complete and robust.
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82 + Split serial.c into serial.c and serialISR.c. serial.c can be
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83 compiled using ARM or THUMB modes. serialISR.c must always be
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84 compiled in ARM mode.
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85 + Another small change to cSerialPutChar().
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89 + In cSerialPutChar() an extra check is made to ensure the post to
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90 the queue was successful if then attempting to retrieve the posted
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96 BASIC INTERRUPT DRIVEN SERIAL PORT DRIVER FOR UART0.
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98 This file contains all the serial port components that can be compiled to
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99 either ARM or THUMB mode. Components that must be compiled to ARM mode are
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100 contained in serialISR.c.
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103 /* Standard includes. */
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104 #include <stdlib.h>
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106 /* Scheduler includes. */
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107 #include "FreeRTOS.h"
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111 /* Demo application includes. */
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112 #include "serial.h"
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114 /*-----------------------------------------------------------*/
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116 /* Constants to setup and access the UART. */
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117 #define serDLAB ( ( unsigned char ) 0x80 )
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118 #define serENABLE_INTERRUPTS ( ( unsigned char ) 0x03 )
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119 #define serNO_PARITY ( ( unsigned char ) 0x00 )
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120 #define ser1_STOP_BIT ( ( unsigned char ) 0x00 )
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121 #define ser8_BIT_CHARS ( ( unsigned char ) 0x03 )
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122 #define serFIFO_ON ( ( unsigned char ) 0x01 )
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123 #define serCLEAR_FIFO ( ( unsigned char ) 0x06 )
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124 #define serWANTED_CLOCK_SCALING ( ( unsigned long ) 16 )
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126 /* Constants to setup and access the VIC. */
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127 #define serUART0_VIC_CHANNEL ( ( unsigned long ) 0x0006 )
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128 #define serUART0_VIC_CHANNEL_BIT ( ( unsigned long ) 0x0040 )
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129 #define serUART0_VIC_ENABLE ( ( unsigned long ) 0x0020 )
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130 #define serCLEAR_VIC_INTERRUPT ( ( unsigned long ) 0 )
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132 #define serINVALID_QUEUE ( ( xQueueHandle ) 0 )
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133 #define serHANDLE ( ( xComPortHandle ) 1 )
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134 #define serNO_BLOCK ( ( portTickType ) 0 )
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136 /*-----------------------------------------------------------*/
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138 /* Queues used to hold received characters, and characters waiting to be
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140 static xQueueHandle xRxedChars;
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141 static xQueueHandle xCharsForTx;
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143 /*-----------------------------------------------------------*/
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145 /* Communication flag between the interrupt service routine and serial API. */
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146 static volatile long *plTHREEmpty;
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149 * The queues are created in serialISR.c as they are used from the ISR.
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150 * Obtain references to the queues and THRE Empty flag.
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152 extern void vSerialISRCreateQueues( unsigned portBASE_TYPE uxQueueLength, xQueueHandle *pxRxedChars, xQueueHandle *pxCharsForTx, long volatile **pplTHREEmptyFlag );
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154 /*-----------------------------------------------------------*/
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156 xComPortHandle xSerialPortInitMinimal( unsigned long ulWantedBaud, unsigned portBASE_TYPE uxQueueLength )
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158 unsigned long ulDivisor, ulWantedClock;
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159 xComPortHandle xReturn = serHANDLE;
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160 extern void ( vUART_ISR_Wrapper )( void );
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162 /* The queues are used in the serial ISR routine, so are created from
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163 serialISR.c (which is always compiled to ARM mode. */
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164 vSerialISRCreateQueues( uxQueueLength, &xRxedChars, &xCharsForTx, &plTHREEmpty );
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167 ( xRxedChars != serINVALID_QUEUE ) &&
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168 ( xCharsForTx != serINVALID_QUEUE ) &&
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169 ( ulWantedBaud != ( unsigned long ) 0 )
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172 portENTER_CRITICAL();
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174 /* Setup the baud rate: Calculate the divisor value. */
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175 ulWantedClock = ulWantedBaud * serWANTED_CLOCK_SCALING;
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176 ulDivisor = configCPU_CLOCK_HZ / ulWantedClock;
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178 /* Set the DLAB bit so we can access the divisor. */
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179 UART0_LCR |= serDLAB;
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181 /* Setup the divisor. */
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182 UART0_DLL = ( unsigned char ) ( ulDivisor & ( unsigned long ) 0xff );
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184 UART0_DLM = ( unsigned char ) ( ulDivisor & ( unsigned long ) 0xff );
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186 /* Turn on the FIFO's and clear the buffers. */
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187 UART0_FCR = ( serFIFO_ON | serCLEAR_FIFO );
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189 /* Setup transmission format. */
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190 UART0_LCR = serNO_PARITY | ser1_STOP_BIT | ser8_BIT_CHARS;
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192 /* Setup the VIC for the UART. */
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193 VICIntSelect &= ~( serUART0_VIC_CHANNEL_BIT );
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194 VICIntEnable |= serUART0_VIC_CHANNEL_BIT;
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195 VICVectAddr1 = ( long ) vUART_ISR_Wrapper;
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196 VICVectCntl1 = serUART0_VIC_CHANNEL | serUART0_VIC_ENABLE;
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198 /* Enable UART0 interrupts. */
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199 UART0_IER |= serENABLE_INTERRUPTS;
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201 portEXIT_CRITICAL();
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205 xReturn = ( xComPortHandle ) 0;
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210 /*-----------------------------------------------------------*/
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212 signed portBASE_TYPE xSerialGetChar( xComPortHandle pxPort, signed char *pcRxedChar, portTickType xBlockTime )
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214 /* The port handle is not required as this driver only supports UART0. */
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217 /* Get the next character from the buffer. Return false if no characters
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218 are available, or arrive before xBlockTime expires. */
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219 if( xQueueReceive( xRxedChars, pcRxedChar, xBlockTime ) )
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228 /*-----------------------------------------------------------*/
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230 void vSerialPutString( xComPortHandle pxPort, const signed char * const pcString, unsigned short usStringLength )
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232 signed char *pxNext;
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234 /* NOTE: This implementation does not handle the queue being full as no
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235 block time is used! */
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237 /* The port handle is not required as this driver only supports UART0. */
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239 ( void ) usStringLength;
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241 /* Send each character in the string, one at a time. */
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242 pxNext = ( signed char * ) pcString;
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245 xSerialPutChar( pxPort, *pxNext, serNO_BLOCK );
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249 /*-----------------------------------------------------------*/
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251 signed portBASE_TYPE xSerialPutChar( xComPortHandle pxPort, signed char cOutChar, portTickType xBlockTime )
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253 signed portBASE_TYPE xReturn;
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255 /* This demo driver only supports one port so the parameter is not used. */
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258 portENTER_CRITICAL();
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260 /* Is there space to write directly to the UART? */
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261 if( *plTHREEmpty == ( long ) pdTRUE )
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263 /* We wrote the character directly to the UART, so was
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265 *plTHREEmpty = pdFALSE;
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266 UART0_THR = cOutChar;
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271 /* We cannot write directly to the UART, so queue the character.
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272 Block for a maximum of xBlockTime if there is no space in the
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274 xReturn = xQueueSend( xCharsForTx, &cOutChar, xBlockTime );
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276 /* Depending on queue sizing and task prioritisation: While we
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277 were blocked waiting to post interrupts were not disabled. It is
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278 possible that the serial ISR has emptied the Tx queue, in which
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279 case we need to start the Tx off again. */
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280 if( ( *plTHREEmpty == ( long ) pdTRUE ) && ( xReturn == pdPASS ) )
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282 xQueueReceive( xCharsForTx, &cOutChar, serNO_BLOCK );
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283 *plTHREEmpty = pdFALSE;
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284 UART0_THR = cOutChar;
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288 portEXIT_CRITICAL();
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292 /*-----------------------------------------------------------*/
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294 void vSerialClose( xComPortHandle xPort )
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296 /* Not supported as not required by the demo application. */
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299 /*-----------------------------------------------------------*/
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