deviceAlpha.h

/*
 * deviceAlpha.h -- PC simulator for the Seneca "Device Alpha" board
 * (Final Project version: adds 4 push buttons and a display-clear call)
 *
 * This header lets finalproject.c compile and run on a normal computer:
 *   - LED / BUZZER state changes are printed as [SIM] messages
 *   - the 7-Segment display is printed as [7SEG] messages
 *   - GetTemperature() returns a realistic room temperature with noise
 *   - the four push buttons PB1..PB4 are simulated through the keyboard:
 *     when the program polls the buttons and no press is pending, the
 *     simulator reads one line from standard input; typing 1, 2, 3 or 4
 *     (then Enter) simulates pressing and releasing that button.
 *
 * On the real lab computer, delete this file and include the official
 * deviceAlpha.h that comes with the Device Alpha software instead.
 */

#ifndef DEVICE_ALPHA_H
#define DEVICE_ALPHA_H

#include <stdio.h>
#include <stdlib.h>

#ifdef _WIN32
#include <windows.h>
#else
#include <unistd.h>
#endif

/* ---- device identifiers ---- */
#define BLUE_LED	0
#define GREEN_LED	1
#define YELLOW_LED	2
#define RED_LED		3

#define BUZZER		0
#define TEMPERATURE_SENSOR 0

#define PB1		1
#define PB2		2
#define PB3		3
#define PB4		4

/* ---- states ---- */
#define OFF		0
#define ON		1
#define RELEASED	0
#define PRESSED		1

static const char *simLedNames[] = { "BLUE", "GREEN", "YELLOW", "RED" };

static void SetLEDState(int led, int state)
{
	printf("        [SIM] %s LED %s\n", simLedNames[led], state == ON ? "ON" : "OFF");
}

static void SetBuzzerState(int buzzer, int state)
{
	(void)buzzer;
	printf("        [SIM] BUZZER %s\n", state == ON ? "ON" : "OFF");
}

static void DisplayIntValue(int value)
{
	printf("        [7SEG] %d\n", value);
}

static void DisplayDoubleValue(double value, int decimals)
{
	printf("        [7SEG] %.*f\n", decimals, value);
}

static void ClearSevenSegmentDisplay(void)
{
	printf("        [7SEG] (cleared)\n");
}

static void Wait(int milliseconds)
{
#ifdef _WIN32
	Sleep(milliseconds);
#else
	usleep((useconds_t)milliseconds * 1000);
#endif
}

static double GetTemperature(int sensor)
{
	(void)sensor;
	/* room temperature about 22 degrees with small noise */
	return 22.0 + ((rand() % 41) - 20) / 100.0;
}

/*
 * Simulated push buttons.
 *
 * simPendingButton  : which button (1..4) is currently "pressed"
 * simPressPollsLeft : how many more polls of that button report PRESSED
 *
 * When every button is released and the program polls any button, the
 * simulator blocks and reads one line from stdin -- exactly like a real
 * system idling until the user presses something.
 */
static int simPendingButton = 0;
static int simPressPollsLeft = 0;

static void simReadNextButtonEvent(void)
{
	char inputLine[64];

	printf("        [SIM] (waiting for a button: type 1=PB1 2=PB2 3=PB3 4=PB4)\n");
	if (fgets(inputLine, sizeof inputLine, stdin) == NULL)
	{
		printf("        [SIM] (end of input - stopping simulation)\n");
		exit(0);
	}

	if (inputLine[0] >= '1' && inputLine[0] <= '4')
	{
		simPendingButton = inputLine[0] - '0';
		simPressPollsLeft = 8;
		printf("        [SIM] PB%d pressed\n", simPendingButton);
	}
	/* anything else: ignored, all buttons stay released this round */
}

static int GetPushButtonState(int button)
{
	int pressedNow;

	if (simPendingButton == 0)
	{
		simReadNextButtonEvent();
	}

	if (simPendingButton == 0)
	{
		return RELEASED;
	}

	/* the press lasts a fixed number of polls, whichever button is polled,
	   so a press that the current state ignores expires on its own */
	simPressPollsLeft--;
	pressedNow = (button == simPendingButton && simPressPollsLeft > 0);

	if (simPressPollsLeft <= 0)
	{
		printf("        [SIM] PB%d released\n", simPendingButton);
		simPendingButton = 0;
	}

	return pressedNow ? PRESSED : RELEASED;
}

#endif /* DEVICE_ALPHA_H */