text: /*
   * FreeRTOS V202111.00
   * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy of
   * this software and associated documentation files (the "Software"), to deal in
   * the Software without restriction, including without limitation the rights to
   * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
   * the Software, and to permit persons to whom the Software is furnished to do so,
   * subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in all
   * copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
   * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
   * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
   * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   *
   * http://www.FreeRTOS.org
   * http://aws.amazon.com/freertos
   *
   * 1 tab == 4 spaces!
   */
  
  
  /*
   * This project contains an application demonstrating the use of the
   * FreeRTOS.org mini real time scheduler on the Luminary Micro LM3S811 Eval
   * board.  See http://www.FreeRTOS.org for more information.
   *
   * main() simply sets up the hardware, creates all the demo application tasks,
   * then starts the scheduler.  http://www.freertos.org/a00102.html provides
   * more information on the standard demo tasks.
   *
   * In addition to a subset of the standard demo application tasks, main.c also
   * defines the following tasks:
   *
   * + A 'Print' task.  The print task is the only task permitted to access the
   * LCD - thus ensuring mutual exclusion and consistent access to the resource.
   * Other tasks do not access the LCD directly, but instead send the text they
   * wish to display to the print task.  The print task spends most of its time
   * blocked - only waking when a message is queued for display.
   *
   * + A 'Button handler' task.  The eval board contains a user push button that
   * is configured to generate interrupts.  The interrupt handler uses a
   * semaphore to wake the button handler task - demonstrating how the priority
   * mechanism can be used to defer interrupt processing to the task level.  The
   * button handler task sends a message both to the LCD (via the print task) and
   * the UART where it can be viewed using a dumb terminal (via the UART to USB
   * converter on the eval board).  NOTES:  The dumb terminal must be closed in
   * order to reflash the microcontroller.  A very basic interrupt driven UART
   * driver is used that does not use the FIFO.  19200 baud is used.
   *
   * + A 'check' task.  The check task only executes every five seconds but has a
   * high priority so is guaranteed to get processor time.  Its function is to
   * check that all the other tasks are still operational and that no errors have
   * been detected at any time.  If no errors have every been detected 'PASS' is
   * written to the display (via the print task) - if an error has ever been
   * detected the message is changed to 'FAIL'.  The position of the message is
   * changed for each write.
   */
  
  
  
  /* Environment includes. */
  #include "DriverLib.h"
  
  /* Scheduler includes. */
  #include "FreeRTOS.h"
  #include "task.h"
  #include "queue.h"
  #include "semphr.h"
  
  /* Demo app includes. */
  #include "integer.h"
  #include "PollQ.h"
  #include "semtest.h"
  #include "BlockQ.h"
  
  /* Delay between cycles of the 'check' task. */
  #define mainCHECK_DELAY						( ( TickType_t ) 5000 / portTICK_PERIOD_MS )
  
  /* UART configuration - note this does not use the FIFO so is not very
  efficient. */
  #define mainBAUD_RATE				( 19200 )
  #define mainFIFO_SET				( 0x10 )
  
  /* Demo task priorities. */
  #define mainQUEUE_POLL_PRIORITY		( tskIDLE_PRIORITY + 2 )
  #define mainCHECK_TASK_PRIORITY		( tskIDLE_PRIORITY + 3 )
  #define mainSEM_TEST_PRIORITY		( tskIDLE_PRIORITY + 1 )
  #define mainBLOCK_Q_PRIORITY		( tskIDLE_PRIORITY + 2 )
  
  /* Demo board specifics. */
  #define mainPUSH_BUTTON             GPIO_PIN_4
  
  /* Misc. */
  #define mainQUEUE_SIZE				( 3 )
  #define mainDEBOUNCE_DELAY			( ( TickType_t ) 150 / portTICK_PERIOD_MS )
  #define mainNO_DELAY				( ( TickType_t ) 0 )
  /*
   * Configure the processor and peripherals for this demo.
   */
  static void prvSetupHardware( void );
  
  /*
   * The 'check' task, as described at the top of this file.
   */
  static void vCheckTask( void *pvParameters );
  
  /*
   * The task that is woken by the ISR that processes GPIO interrupts originating
   * from the push button.
   */
  static void vButtonHandlerTask( void *pvParameters );
  
  /*
   * The task that controls access to the LCD.
   */
  static void vPrintTask( void *pvParameter );
  
  /* String that is transmitted on the UART. */
  static char *cMessage = "Task woken by button interrupt! --- ";
  static volatile char *pcNextChar;
  
  /* The semaphore used to wake the button handler task from within the GPIO
  interrupt handler. */
  SemaphoreHandle_t xButtonSemaphore;
  
  /* The queue used to send strings to the print task for display on the LCD. */
  QueueHandle_t xPrintQueue;
  
  /*-----------------------------------------------------------*/
  
  int main( void )
  {
  	/* Configure the clocks, UART and GPIO. */
  	prvSetupHardware();
  
  	/* Create the semaphore used to wake the button handler task from the GPIO
  	ISR. */
  	vSemaphoreCreateBinary( xButtonSemaphore );
  	xSemaphoreTake( xButtonSemaphore, 0 );
  
  	/* Create the queue used to pass message to vPrintTask. */
  	xPrintQueue = xQueueCreate( mainQUEUE_SIZE, sizeof( char * ) );
  
  	/* Start the standard demo tasks. */
  	vStartIntegerMathTasks( tskIDLE_PRIORITY );
  	vStartPolledQueueTasks( mainQUEUE_POLL_PRIORITY );
  	vStartSemaphoreTasks( mainSEM_TEST_PRIORITY );
  	vStartBlockingQueueTasks( mainBLOCK_Q_PRIORITY );
  
  	/* Start the tasks defined within the file. */
  	xTaskCreate( vCheckTask, "Check", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY, NULL );
  	xTaskCreate( vButtonHandlerTask, "Status", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY + 1, NULL );
  	xTaskCreate( vPrintTask, "Print", configMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY - 1, NULL );
  
  	/* Start the scheduler. */
  	vTaskStartScheduler();
  
  	/* Will only get here if there was insufficient heap to start the
  	scheduler. */
  
  	return 0;
  }
  /*-----------------------------------------------------------*/
  
  static void vCheckTask( void *pvParameters )
  {
  portBASE_TYPE xErrorOccurred = pdFALSE;
  TickType_t xLastExecutionTime;
  const char *pcPassMessage = "PASS";
  const char *pcFailMessage = "FAIL";
  
  	/* Initialise xLastExecutionTime so the first call to vTaskDelayUntil()
  	works correctly. */
  	xLastExecutionTime = xTaskGetTickCount();
  
  	for( ;; )
  	{
  		/* Perform this check every mainCHECK_DELAY milliseconds. */
  		vTaskDelayUntil( &xLastExecutionTime, mainCHECK_DELAY );
  
  		/* Has an error been found in any task? */
  
  		if( xAreIntegerMathsTaskStillRunning() != pdTRUE )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  	
  		if( xArePollingQueuesStillRunning() != pdTRUE )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  	
  		if( xAreSemaphoreTasksStillRunning() != pdTRUE )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  
  		if( xAreBlockingQueuesStillRunning() != pdTRUE )
  		{
  			xErrorOccurred = pdTRUE;
  		}
  
  		/* Send either a pass or fail message.  If an error is found it is
  		never cleared again.  We do not write directly to the LCD, but instead
  		queue a message for display by the print task. */
  		if( xErrorOccurred == pdTRUE )
  		{
  			xQueueSend( xPrintQueue, &pcFailMessage, portMAX_DELAY );
  		}
  		else
  		{
  			xQueueSend( xPrintQueue, &pcPassMessage, portMAX_DELAY );
  		}
  	}
  }
  /*-----------------------------------------------------------*/
  
  static void prvSetupHardware( void )
  {
  	/* Setup the PLL. */
  	SysCtlClockSet( SYSCTL_SYSDIV_10 | SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_6MHZ );
  
  	/* Setup the push button. */
  	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);
      GPIODirModeSet(GPIO_PORTC_BASE, mainPUSH_BUTTON, GPIO_DIR_MODE_IN);
  	GPIOIntTypeSet( GPIO_PORTC_BASE, mainPUSH_BUTTON,GPIO_FALLING_EDGE );
  	IntPrioritySet( INT_GPIOC, configKERNEL_INTERRUPT_PRIORITY );
  	GPIOPinIntEnable( GPIO_PORTC_BASE, mainPUSH_BUTTON );
  	IntEnable( INT_GPIOC );
  
  
  
  	/* Enable the UART.  */
  	SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
  	SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
  
  	/* Set GPIO A0 and A1 as peripheral function.  They are used to output the
  	UART signals. */
  	GPIODirModeSet( GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1, GPIO_DIR_MODE_HW );
  
  	/* Configure the UART for 8-N-1 operation. */
  	UARTConfigSetExpClk( UART0_BASE, SysCtlClockGet(), mainBAUD_RATE, UART_CONFIG_WLEN_8 | UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE );
  
  	/* We don't want to use the fifo.  This is for test purposes to generate
  	as many interrupts as possible. */
  	HWREG( UART0_BASE + UART_O_LCR_H ) &= ~mainFIFO_SET;
  
  	/* Enable Tx interrupts. */
  	HWREG( UART0_BASE + UART_O_IM ) |= UART_INT_TX;
  	IntPrioritySet( INT_UART0, configKERNEL_INTERRUPT_PRIORITY );
  	IntEnable( INT_UART0 );
  
  
  	/* Initialise the LCD> */
      OSRAMInit( false );
      OSRAMStringDraw("www.FreeRTOS.org", 0, 0);
  	OSRAMStringDraw("LM3S811 demo", 16, 1);
  }
  /*-----------------------------------------------------------*/
  
  static void vButtonHandlerTask( void *pvParameters )
  {
  const char *pcInterruptMessage = "Int";
  
  	for( ;; )
  	{
  		/* Wait for a GPIO interrupt to wake this task. */
  		while( xSemaphoreTake( xButtonSemaphore, portMAX_DELAY ) != pdPASS );
  
  		/* Start the Tx of the message on the UART. */
  		UARTIntDisable( UART0_BASE, UART_INT_TX );
  		{
  			pcNextChar = cMessage;
  
  			/* Send the first character. */
  			if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
  			{
  				HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
  			}
  
  			pcNextChar++;
  		}
  		UARTIntEnable(UART0_BASE, UART_INT_TX);
  
  		/* Queue a message for the print task to display on the LCD. */
  		xQueueSend( xPrintQueue, &pcInterruptMessage, portMAX_DELAY );
  
  		/* Make sure we don't process bounces. */
  		vTaskDelay( mainDEBOUNCE_DELAY );
  		xSemaphoreTake( xButtonSemaphore, mainNO_DELAY );
  	}
  }
  
  /*-----------------------------------------------------------*/
  
  void vUART_ISR(void)
  {
  unsigned long ulStatus;
  
  	/* What caused the interrupt. */
  	ulStatus = UARTIntStatus( UART0_BASE, pdTRUE );
  
  	/* Clear the interrupt. */
  	UARTIntClear( UART0_BASE, ulStatus );
  
  	/* Was a Tx interrupt pending? */
  	if( ulStatus & UART_INT_TX )
  	{
  		/* Send the next character in the string.  We are not using the FIFO. */
  		if( *pcNextChar != NULL )
  		{
  			if( !( HWREG( UART0_BASE + UART_O_FR ) & UART_FR_TXFF ) )
  			{
  				HWREG( UART0_BASE + UART_O_DR ) = *pcNextChar;
  			}
  			pcNextChar++;
  		}
  	}
  }
  /*-----------------------------------------------------------*/
  
  void vGPIO_ISR( void )
  {
  portBASE_TYPE xHigherPriorityTaskWoken = pdFALSE;
  
  	/* Clear the interrupt. */
  	GPIOPinIntClear(GPIO_PORTC_BASE, mainPUSH_BUTTON);
  
  	/* Wake the button handler task. */
  	xSemaphoreGiveFromISR( xButtonSemaphore, &xHigherPriorityTaskWoken );
  	portEND_SWITCHING_ISR( xHigherPriorityTaskWoken );
  }
  /*-----------------------------------------------------------*/
  
  static void vPrintTask( void *pvParameters )
  {
  char *pcMessage;
  unsigned portBASE_TYPE uxLine = 0, uxRow = 0;
  
  	for( ;; )
  	{
  		/* Wait for a message to arrive. */
  		xQueueReceive( xPrintQueue, &pcMessage, portMAX_DELAY );
  
  		/* Write the message to the LCD. */
  		uxRow++;
  		uxLine++;
  		OSRAMClear();
  		OSRAMStringDraw( pcMessage, uxLine & 0x3f, uxRow & 0x01);
  	}
  }
  
  