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/*
FreeRTOS V8.0.1 - Copyright (C) 2014 Real Time Engineers Ltd.
All rights reserved
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***************************************************************************
* *
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***************************************************************************
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FreeRTOS is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License (version 2) as published by the
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>>! NOTE: The modification to the GPL is included to allow you to !<<
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FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
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FOR A PARTICULAR PURPOSE. Full license text is available from the following
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* *
* Having a problem? Start by reading the FAQ "My application does *
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* *
* http://www.FreeRTOS.org/FAQHelp.html *
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*/
/*
* 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);
}
}