FreeRTOS-Kernel/Demo/CORTUS_APS3_GCC/Demo/7seg.c

/*
    FreeRTOS V7.0.2 - Copyright (C) 2011 Real Time Engineers Ltd.
	

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    This file is part of the FreeRTOS distribution.

    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
    Free Software Foundation AND MODIFIED BY the FreeRTOS exception.
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*/


#include <stdlib.h>

/* Scheduler include files. */
#include "FreeRTOS.h"
#include "task.h"

/* Demo program include files. */
#include "7seg.h"
#include "demoGpio.h"

#define x7segSTACK_SIZE			configMINIMAL_STACK_SIZE

static void prvRefreshTask( void *pvParameters );
static void prvCountTask( void *pvParameters );

/* Value to output to 7 segment display
led_digits[0] is the right most digit */
static signed char seg7_digits[4];

void vStart7SegTasks( unsigned portBASE_TYPE uxPriority )
{
	xTaskCreate( prvRefreshTask, ( signed char * ) "7SegRefresh", x7segSTACK_SIZE, NULL, uxPriority, ( xTaskHandle *) NULL );
	xTaskCreate( prvCountTask,   ( signed char * ) "7SegCount",	x7segSTACK_SIZE, NULL, uxPriority, ( xTaskHandle *) NULL );
}
/*-----------------------------------------------------------*/

static void prvRefreshTask( void *pvParameters )
{
/* This is table 3.3 from the Spartan-3 Starter Kit board user guide */
const unsigned char bits[ 16 ] =
{
	0x01,
	0x4f,
	0x12,
	0x06,
	0x4c,
	0x24,
	0x20,
	0x0f,
	0x00,
	0x04,
	0x08,
	0x60,
	0x31,
	0x42,
	0x30,
	0x38
};

const unsigned char apsx[4] =
{
	0x06, /* 3 */
	0x24, /* S */
	0x18, /* P */
	0x08  /* A */
};

portTickType xRefreshRate, xLastRefreshTime;

/* Digit to scan */
static int d = 0;

	xRefreshRate = 2;

	/* We need to initialise xLastRefreshTime prior to the first call to
	vTaskDelayUntil(). */
	xLastRefreshTime = xTaskGetTickCount();

	for (;;)
	{
		for( d = 0; d < 4; d++ )
		{
			vTaskDelayUntil ( &xLastRefreshTime, xRefreshRate );

			/* Display digit */
			gpio->out.an  = -1;
			if( ( seg7_digits[ 1 ] == 4 ) || ( seg7_digits[ 1 ] == 5 ) )
			{
				gpio->out.digit = apsx[ d ];
			}
			else
			{
				gpio->out.digit = bits[ seg7_digits[ d ] ];
			}

			gpio->out.dp = 1;
			gpio->out.an  = ~(1 << d);
		}
	}
}
/*-----------------------------------------------------------*/

static void prvCountTask( void *pvParameters )
{
portTickType xCountRate, xLastCountTime;

	/* Approximately 20HZ */
	xCountRate = configTICK_RATE_HZ / 20;

	/* We need to initialise xLastCountTime prior to the first call to
	vTaskDelayUntil(). */
	xLastCountTime = xTaskGetTickCount();

	for (;;)
	{
		vTaskDelayUntil( &xLastCountTime, xCountRate );

		/* Really ugly way to do BCD arithmetic.... */
		seg7_digits[ 0 ] -= 1;
		if( seg7_digits[ 0 ] < 0 )
		{
			seg7_digits[ 0 ] = 9;
			seg7_digits[ 1 ] -= 1;
			if( seg7_digits[ 1 ] < 0 )
			{
				seg7_digits[ 1 ] = 9;
				seg7_digits[ 2 ] -= 1;
				if( seg7_digits[ 2 ] < 0 )
				{
					seg7_digits[ 2 ] = 9;
					seg7_digits[ 3 ] -= 1;
					if( seg7_digits[ 3 ] < 0 )
					{
						seg7_digits[ 3 ] = 9;
					}
				}
			}
		}
	}
}