2 FreeRTOS V7.2.0 - Copyright (C) 2012 Real Time Engineers Ltd.
\r
5 ***************************************************************************
\r
7 * FreeRTOS tutorial books are available in pdf and paperback. *
\r
8 * Complete, revised, and edited pdf reference manuals are also *
\r
11 * Purchasing FreeRTOS documentation will not only help you, by *
\r
12 * ensuring you get running as quickly as possible and with an *
\r
13 * in-depth knowledge of how to use FreeRTOS, it will also help *
\r
14 * the FreeRTOS project to continue with its mission of providing *
\r
15 * professional grade, cross platform, de facto standard solutions *
\r
16 * for microcontrollers - completely free of charge! *
\r
18 * >>> See http://www.FreeRTOS.org/Documentation for details. <<< *
\r
20 * Thank you for using FreeRTOS, and thank you for your support! *
\r
22 ***************************************************************************
\r
25 This file is part of the FreeRTOS distribution.
\r
27 FreeRTOS is free software; you can redistribute it and/or modify it under
\r
28 the terms of the GNU General Public License (version 2) as published by the
\r
29 Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
\r
30 >>>NOTE<<< The modification to the GPL is included to allow you to
\r
31 distribute a combined work that includes FreeRTOS without being obliged to
\r
32 provide the source code for proprietary components outside of the FreeRTOS
\r
33 kernel. FreeRTOS is distributed in the hope that it will be useful, but
\r
34 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
\r
35 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
\r
36 more details. You should have received a copy of the GNU General Public
\r
37 License and the FreeRTOS license exception along with FreeRTOS; if not it
\r
38 can be viewed here: http://www.freertos.org/a00114.html and also obtained
\r
39 by writing to Richard Barry, contact details for whom are available on the
\r
44 ***************************************************************************
\r
46 * Having a problem? Start by reading the FAQ "My application does *
\r
47 * not run, what could be wrong? *
\r
49 * http://www.FreeRTOS.org/FAQHelp.html *
\r
51 ***************************************************************************
\r
54 http://www.FreeRTOS.org - Documentation, training, latest information,
\r
55 license and contact details.
\r
57 http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
\r
58 including FreeRTOS+Trace - an indispensable productivity tool.
\r
60 Real Time Engineers ltd license FreeRTOS to High Integrity Systems, who sell
\r
61 the code with commercial support, indemnification, and middleware, under
\r
62 the OpenRTOS brand: http://www.OpenRTOS.com. High Integrity Systems also
\r
63 provide a safety engineered and independently SIL3 certified version under
\r
64 the SafeRTOS brand: http://www.SafeRTOS.com.
\r
67 /* Scheduler includes. */
\r
68 #include "FreeRTOS.h"
\r
72 /* Demo includes. */
\r
76 * The LCD is written to by more than one task so is controlled by this
\r
77 * 'gatekeeper' task. This is the only task that is actually permitted to
\r
78 * access the LCD directly. Other tasks wanting to display a message send
\r
79 * the message to the gatekeeper.
\r
81 static void vLCDTask( void *pvParameters );
\r
84 * Setup the peripherals required to communicate with the LCD.
\r
86 static void prvSetupLCD( void );
\r
89 * Move to the first (0) or second (1) row of the LCD.
\r
91 static void prvLCDGotoRow( unsigned portSHORT usRow );
\r
94 * Write a string of text to the LCD.
\r
96 static void prvLCDPutString( portCHAR *pcString );
\r
101 static void prvLCDClear( void );
\r
103 /*-----------------------------------------------------------*/
\r
105 /* Brief delay to permit the LCD to catch up with commands. */
\r
106 #define lcdVERY_SHORT_DELAY ( 1 )
\r
107 #define lcdSHORT_DELAY ( 4 / portTICK_RATE_MS )
\r
108 #define lcdLONG_DELAY ( 15 / portTICK_RATE_MS )
\r
110 /* LCD commands. */
\r
111 #define lcdCLEAR ( 0x01 )
\r
112 #define lcdHOME ( 0x02 )
\r
113 #define lcdLINE2 ( 0xc0 )
\r
115 /* SFR that seems to be missing from the standard header files. */
\r
116 #define PMAEN *( ( unsigned short * ) 0x60c )
\r
118 /* LCD R/W signal. */
\r
119 #define lcdRW LATDbits.LATD5
\r
121 /* LCD lcdRS signal. */
\r
122 #define lcdRS LATBbits.LATB15
\r
124 /* LCD lcdE signal . */
\r
125 #define lcdE LATDbits.LATD4
\r
127 /* Control signal pin direction. */
\r
128 #define RW_TRIS TRISDbits.TRISD5
\r
129 #define RS_TRIS TRISBbits.TRISB15
\r
130 #define E_TRIS TRISDbits.TRISD4
\r
132 /* Port for LCD data */
\r
133 #define lcdDATA LATE
\r
134 #define lcdDATAPORT PORTE
\r
136 /* I/O setup for data Port. */
\r
137 #define TRISDATA TRISE
\r
139 /* The length of the queue used to send messages to the LCD gatekeeper task. */
\r
140 #define lcdQUEUE_SIZE 3
\r
141 /*-----------------------------------------------------------*/
\r
143 /* The queue used to send messages to the LCD task. */
\r
144 xQueueHandle xLCDQueue;
\r
146 static void prvLCDCommand( portCHAR cCommand );
\r
147 static void prvLCDData( portCHAR cChar );
\r
149 /*-----------------------------------------------------------*/
\r
151 xQueueHandle xStartLCDTask( void )
\r
153 /* Create the queue used by the LCD task. Messages for display on the LCD
\r
154 are received via this queue. */
\r
155 xLCDQueue = xQueueCreate( lcdQUEUE_SIZE, sizeof( xLCDMessage ) );
\r
157 /* Start the task that will write to the LCD. The LCD hardware is
\r
158 initialised from within the task itself so delays can be used. */
\r
159 xTaskCreate( vLCDTask, ( signed portCHAR * ) "LCD", configMINIMAL_STACK_SIZE, NULL, tskIDLE_PRIORITY + 1, NULL );
\r
163 /*-----------------------------------------------------------*/
\r
165 static void prvLCDGotoRow( unsigned portSHORT usRow )
\r
169 prvLCDCommand( lcdHOME );
\r
173 prvLCDCommand( lcdLINE2 );
\r
176 /*-----------------------------------------------------------*/
\r
178 static void prvLCDCommand( portCHAR cCommand )
\r
180 /* Prepare RD0 - RD7. */
\r
181 lcdDATA &= 0xFF00;
\r
183 /* Command byte to lcd. */
\r
184 lcdDATA |= cCommand;
\r
186 /* Ensure lcdRW is 0. */
\r
190 /* Toggle lcdE line. */
\r
192 vTaskDelay( lcdVERY_SHORT_DELAY );
\r
195 vTaskDelay( lcdSHORT_DELAY );
\r
197 /*-----------------------------------------------------------*/
\r
199 static void prvLCDData( portCHAR cChar )
\r
201 /* ensure lcdRW is 0. */
\r
204 /* Assert register select to 1. */
\r
207 /* Prepare RD0 - RD7. */
\r
208 lcdDATA &= 0xFF00;
\r
210 /* Data byte to lcd. */
\r
217 /* Toggle lcdE signal. */
\r
220 /* Negate register select to 0. */
\r
223 vTaskDelay( lcdVERY_SHORT_DELAY );
\r
225 /*-----------------------------------------------------------*/
\r
227 static void prvLCDPutString( portCHAR *pcString )
\r
229 /* Write out each character with appropriate delay between each. */
\r
232 prvLCDData( *pcString );
\r
234 vTaskDelay( lcdSHORT_DELAY );
\r
237 /*-----------------------------------------------------------*/
\r
239 static void prvLCDClear( void )
\r
241 prvLCDCommand( lcdCLEAR );
\r
243 /*-----------------------------------------------------------*/
\r
245 static void prvSetupLCD( void )
\r
247 /* Wait for proper power up. */
\r
248 vTaskDelay( lcdLONG_DELAY );
\r
250 /* Set initial states for the data and control pins */
\r
253 /* R/W state set low. */
\r
256 /* lcdRS state set low. */
\r
259 /* lcdE state set low. */
\r
262 /* Set data and control pins to outputs */
\r
265 /* lcdRW pin set as output. */
\r
268 /* lcdRS pin set as output. */
\r
271 /* lcdE pin set as output. */
\r
274 /* 1st LCD initialization sequence */
\r
282 /* Toggle lcdE signal. */
\r
285 vTaskDelay( lcdSHORT_DELAY );
\r
286 vTaskDelay( lcdSHORT_DELAY );
\r
287 vTaskDelay( lcdSHORT_DELAY );
\r
289 /* 2nd LCD initialization sequence */
\r
297 /* Toggle lcdE signal. */
\r
300 vTaskDelay( lcdSHORT_DELAY );
\r
302 /* 3rd LCD initialization sequence */
\r
310 /* Toggle lcdE signal. */
\r
313 vTaskDelay( lcdSHORT_DELAY );
\r
316 /* Function set. */
\r
317 prvLCDCommand( 0x38 );
\r
319 /* Display on/off control, cursor blink off (0x0C). */
\r
320 prvLCDCommand( 0x0C );
\r
322 /* Entry mode set (0x06). */
\r
323 prvLCDCommand( 0x06 );
\r
325 prvLCDCommand( lcdCLEAR );
\r
327 /*-----------------------------------------------------------*/
\r
329 static void vLCDTask( void *pvParameters )
\r
331 xLCDMessage xMessage;
\r
332 unsigned portSHORT usRow = 0;
\r
334 /* Initialise the hardware. This uses delays so must not be called prior
\r
335 to the scheduler being started. */
\r
338 /* Welcome message. */
\r
339 prvLCDPutString( "www.FreeRTOS.org" );
\r
343 /* Wait for a message to arrive that requires displaying. */
\r
344 while( xQueueReceive( xLCDQueue, &xMessage, portMAX_DELAY ) != pdPASS );
\r
346 /* Clear the current display value. */
\r
349 /* Switch rows each time so we can see that the display is still being
\r
351 prvLCDGotoRow( usRow & 0x01 );
\r
353 prvLCDPutString( xMessage.pcMessage );
\r
355 /* Delay the requested amount of time to ensure the text just written
\r
356 to the LCD is not overwritten. */
\r
357 vTaskDelay( xMessage.xMinDisplayTime );
\r