2 * FreeRTOS Kernel V10.2.0
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3 * Copyright (C) 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://www.FreeRTOS.org
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23 * http://aws.amazon.com/freertos
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25 * 1 tab == 4 spaces!
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30 * This project contains an application demonstrating the use of the
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31 * FreeRTOS.org mini real time scheduler on the Luminary Micro LM3S811 Eval
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32 * board. See http://www.FreeRTOS.org for more information.
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34 * main() simply sets up the hardware, creates all the demo application tasks,
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35 * then starts the scheduler. http://www.freertos.org/a00102.html provides
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36 * more information on the standard demo tasks.
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38 * In addition to a subset of the standard demo application tasks, main.c also
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39 * defines the following tasks:
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41 * + A 'Print' task. The print task is the only task permitted to access the
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42 * LCD - thus ensuring mutual exclusion and consistent access to the resource.
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43 * Other tasks do not access the LCD directly, but instead send the text they
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44 * wish to display to the print task. The print task spends most of its time
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45 * blocked - only waking when a message is queued for display.
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47 * + A 'Button handler' task. The eval board contains a user push button that
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48 * is configured to generate interrupts. The interrupt handler uses a
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49 * semaphore to wake the button handler task - demonstrating how the priority
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50 * mechanism can be used to defer interrupt processing to the task level. The
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51 * button handler task sends a message both to the LCD (via the print task) and
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52 * the UART where it can be viewed using a dumb terminal (via the UART to USB
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53 * converter on the eval board). NOTES: The dumb terminal must be closed in
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54 * order to reflash the microcontroller. A very basic interrupt driven UART
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55 * driver is used that does not use the FIFO. 19200 baud is used.
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57 * + A 'check' task. The check task only executes every five seconds but has a
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58 * high priority so is guaranteed to get processor time. Its function is to
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59 * check that all the other tasks are still operational and that no errors have
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60 * been detected at any time. If no errors have every been detected 'PASS' is
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61 * written to the display (via the print task) - if an error has ever been
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62 * detected the message is changed to 'FAIL'. The position of the message is
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63 * changed for each write.
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68 /* Environment includes. */
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69 #include "DriverLib.h"
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71 /* Scheduler includes. */
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72 #include "FreeRTOS.h"
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77 /* Demo app includes. */
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78 #include "integer.h"
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80 #include "semtest.h"
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83 /* Delay between cycles of the 'check' task. */
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84 #define mainCHECK_DELAY ( ( TickType_t ) 5000 / portTICK_PERIOD_MS )
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86 /* UART configuration - note this does not use the FIFO so is not very
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88 #define mainBAUD_RATE ( 19200 )
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89 #define mainFIFO_SET ( 0x10 )
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91 /* Demo task priorities. */
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92 #define mainQUEUE_POLL_PRIORITY ( tskIDLE_PRIORITY + 2 )
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93 #define mainCHECK_TASK_PRIORITY ( tskIDLE_PRIORITY + 3 )
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94 #define mainSEM_TEST_PRIORITY ( tskIDLE_PRIORITY + 1 )
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95 #define mainBLOCK_Q_PRIORITY ( tskIDLE_PRIORITY + 2 )
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97 /* Demo board specifics. */
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98 #define mainPUSH_BUTTON GPIO_PIN_4
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101 #define mainQUEUE_SIZE ( 3 )
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102 #define mainDEBOUNCE_DELAY ( ( TickType_t ) 150 / portTICK_PERIOD_MS )
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103 #define mainNO_DELAY ( ( TickType_t ) 0 )
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105 * Configure the processor and peripherals for this demo.
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107 static void prvSetupHardware( void );
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110 * The 'check' task, as described at the top of this file.
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112 static void vCheckTask( void *pvParameters );
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115 * The task that is woken by the ISR that processes GPIO interrupts originating
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116 * from the push button.
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118 static void vButtonHandlerTask( void *pvParameters );
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121 * The task that controls access to the LCD.
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123 static void vPrintTask( void *pvParameter );
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125 /* String that is transmitted on the UART. */
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126 static char *cMessage = "Task woken by button interrupt! --- ";
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127 static volatile char *pcNextChar;
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129 /* The semaphore used to wake the button handler task from within the GPIO
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130 interrupt handler. */
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131 SemaphoreHandle_t xButtonSemaphore;
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133 /* The queue used to send strings to the print task for display on the LCD. */
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134 QueueHandle_t xPrintQueue;
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136 /*-----------------------------------------------------------*/
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140 /* Configure the clocks, UART and GPIO. */
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141 prvSetupHardware();
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143 /* Create the semaphore used to wake the button handler task from the GPIO
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145 vSemaphoreCreateBinary( xButtonSemaphore );
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146 xSemaphoreTake( xButtonSemaphore, 0 );
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148 /* Create the queue used to pass message to vPrintTask. */
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149 xPrintQueue = xQueueCreate( mainQUEUE_SIZE, sizeof( char * ) );
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151 /* Start the standard demo tasks. */
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152 vStartIntegerMathTasks( tskIDLE_PRIORITY );
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153 vStartPolledQueueTasks( mainQUEUE_POLL_PRIORITY );
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154 vStartSemaphoreTasks( mainSEM_TEST_PRIORITY );
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155 vStartBlockingQueueTasks( mainBLOCK_Q_PRIORITY );
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157 /* Start the tasks defined within the file. */
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158 xTaskCreate( vCheckTask, "Check", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY, NULL );
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159 xTaskCreate( vButtonHandlerTask, "Status", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY + 1, NULL );
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160 xTaskCreate( vPrintTask, "Print", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY - 1, NULL );
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162 /* Start the scheduler. */
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163 vTaskStartScheduler();
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165 /* Will only get here if there was insufficient heap to start the
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170 /*-----------------------------------------------------------*/
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172 static void vCheckTask( void *pvParameters )
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174 portBASE_TYPE xErrorOccurred = pdFALSE;
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175 TickType_t xLastExecutionTime;
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176 const char *pcPassMessage = "PASS";
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177 const char *pcFailMessage = "FAIL";
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179 /* Initialise xLastExecutionTime so the first call to vTaskDelayUntil()
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180 works correctly. */
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181 xLastExecutionTime = xTaskGetTickCount();
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185 /* Perform this check every mainCHECK_DELAY milliseconds. */
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186 vTaskDelayUntil( &xLastExecutionTime, mainCHECK_DELAY );
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188 /* Has an error been found in any task? */
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190 if( xAreIntegerMathsTaskStillRunning() != pdTRUE )
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192 xErrorOccurred = pdTRUE;
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195 if( xArePollingQueuesStillRunning() != pdTRUE )
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197 xErrorOccurred = pdTRUE;
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200 if( xAreSemaphoreTasksStillRunning() != pdTRUE )
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202 xErrorOccurred = pdTRUE;
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205 if( xAreBlockingQueuesStillRunning() != pdTRUE )
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207 xErrorOccurred = pdTRUE;
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210 /* Send either a pass or fail message. If an error is found it is
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211 never cleared again. We do not write directly to the LCD, but instead
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212 queue a message for display by the print task. */
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213 if( xErrorOccurred == pdTRUE )
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215 xQueueSend( xPrintQueue, &pcFailMessage, portMAX_DELAY );
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219 xQueueSend( xPrintQueue, &pcPassMessage, portMAX_DELAY );
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223 /*-----------------------------------------------------------*/
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225 static void prvSetupHardware( void )
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227 /* Setup the PLL. */
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228 SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
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230 /* Setup the push button. */
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231 SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
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232 GPIODirModeSet(GPIO_PORTC_BASE, mainPUSH_BUTTON, GPIO_DIR_MODE_IN);
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233 GPIOIntTypeSet( GPIO_PORTC_BASE, mainPUSH_BUTTON,GPIO_FALLING_EDGE );
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234 IntPrioritySet( INT_GPIOC, configKERNEL_INTERRUPT_PRIORITY );
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235 GPIOPinIntEnable( GPIO_PORTC_BASE, mainPUSH_BUTTON );
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236 IntEnable( INT_GPIOC );
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240 /* Enable the UART. */
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241 SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
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242 SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
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244 /* Set GPIO A0 and A1 as peripheral function. They are used to output the
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246 GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
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248 /* Configure the UART for 8-N-1 operation. */
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249 UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
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251 /* We don't want to use the fifo. This is for test purposes to generate
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252 as many interrupts as possible. */
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253 HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
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255 /* Enable Tx interrupts. */
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256 HWREG( UART0_BASE + UART_O_IM ) |= UART_INT_TX;
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257 IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
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258 IntEnable( INT_UART0 );
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261 /* Initialise the LCD> */
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262 OSRAMInit( false );
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263 OSRAMStringDraw("www.FreeRTOS.org", 0, 0);
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264 OSRAMStringDraw("LM3S811 demo", 16, 1);
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266 /*-----------------------------------------------------------*/
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268 static void vButtonHandlerTask( void *pvParameters )
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270 const char *pcInterruptMessage = "Int";
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274 /* Wait for a GPIO interrupt to wake this task. */
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275 while( xSemaphoreTake( xButtonSemaphore, portMAX_DELAY ) != pdPASS );
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277 /* Start the Tx of the message on the UART. */
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278 UARTIntDisable( UART0_BASE, UART_INT_TX );
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280 pcNextChar = cMessage;
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282 /* Send the first character. */
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283 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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285 HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
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290 UARTIntEnable(UART0_BASE, UART_INT_TX);
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292 /* Queue a message for the print task to display on the LCD. */
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293 xQueueSend( xPrintQueue, &pcInterruptMessage, portMAX_DELAY );
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295 /* Make sure we don't process bounces. */
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296 vTaskDelay( mainDEBOUNCE_DELAY );
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297 xSemaphoreTake( xButtonSemaphore, mainNO_DELAY );
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301 /*-----------------------------------------------------------*/
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303 void vUART_ISR(void)
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305 unsigned long ulStatus;
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307 /* What caused the interrupt. */
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308 ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
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310 /* Clear the interrupt. */
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311 UARTIntClear( UART0_BASE, ulStatus );
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313 /* Was a Tx interrupt pending? */
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314 if( ulStatus & UART_INT_TX )
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316 /* Send the next character in the string. We are not using the FIFO. */
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317 if( *pcNextChar != NULL )
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319 if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
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321 HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
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327 /*-----------------------------------------------------------*/
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329 void vGPIO_ISR( void )
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331 portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
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333 /* Clear the interrupt. */
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334 GPIOPinIntClear(GPIO_PORTC_BASE, mainPUSH_BUTTON);
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336 /* Wake the button handler task. */
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337 xSemaphoreGiveFromISR( xButtonSemaphore, &xHigherPriorityTaskWoken );
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338 portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
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340 /*-----------------------------------------------------------*/
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342 static void vPrintTask( void *pvParameters )
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345 unsigned portBASE_TYPE uxLine = 0, uxRow = 0;
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349 /* Wait for a message to arrive. */
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350 xQueueReceive( xPrintQueue, &pcMessage, portMAX_DELAY );
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352 /* Write the message to the LCD. */
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356 OSRAMStringDraw( pcMessage, uxLine & 0x3f, uxRow & 0x01);
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