traffic.c

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/**************************************************************************
 *
 * ARM Strategic Support Group
 *
 ***************************************************************************/

/***************************************************************************
 *
 * Module		: traffic.c
 * Description 	: Traffic light program is designed to simulate the US and 
 *				  European Traffic Light System. It is designed to work 
 *				  with the ARM Evaluator7T Board. 
 * Tool Chain	: ARM Developer Suite v1.0
 * Platform		: Evaluator7T 
 * History		:
 *
 *		980301 ASloss
 *		- started working on the design and structure.
 *
 *		980408 ASloss
 *		- added in-line assembler example.
 *
 *		980428 ASloss
 *		- added interrupt handler
 *
 *		980911 ASloss
 *		- added switch_write to output reset banner
 *
 *		990202 ASloss
 *		- added Multi-ICE support
 *
 *		2000-03-27 Andrew N. Sloss
 *		- ported to Evaluator7T
 *
 **************************************************************************/

/**************************************************************************
 * IMPORTS
 **************************************************************************/

#include <stdio.h>
#include <assert.h>

#include "timer.h"
#include "led.h"
#include "irq_ser.h"
#include "segment.h"

/**************************************************************************
 * MACROS
 **************************************************************************/

/* -- uncomment for EUROPEAN style traffic lights ..... */

#define		EUROPEAN		1 

/* -- Non embedded library ............................ */

// #define 	FULL_LIB	1	

#define		DEBUG		1
#define		HARDWARE	1

#define 	LIGHT		int
#define		RED			0
#define		AMBER		1
#define		GREEN		2
#define		COMPLETE	3

#define		STATE		int
#define		ON			1
#define		OFF			0

#define		pRED		active.light_red
#define		pAMBER		active.light_amber
#define		pGREEN		active.light_green

#define		angel_SWI	0x123456

#define 	MAXCYCLES	100000 // maximum number of cycles ......

/**************************************************************************
 * MISC
 **************************************************************************/

__swi (angel_SWI) void _Exit(unsigned op, unsigned except);
#define Exit() _Exit(0x18,0x20026) 

__swi (angel_SWI) void _WriteC(unsigned op, const char *c);
#define WriteC(c) _WriteC (0x3,c)

/**************************************************************************
 * DATATYPES
 **************************************************************************/

typedef struct {

	LIGHT			light_red;
	LIGHT			light_amber;
	LIGHT			light_green;

} traffic_lightstr;

/**************************************************************************
 * STATICS
 **************************************************************************/

static traffic_lightstr		active;
static int					toggle 	= 0;
static int 					cycles 	= 0; // start of the cycles...
static int					phase	= 0; // start of the traffic phase
	
/**************************************************************************
 * ROUTINUES
 **************************************************************************/

/* -- traffic_change -----------------------------------------------------
 *
 * Description	: This routine changes the state of a particular LED.
 *
 * Parameters	: LIGHT w -  RED | GREEN | AMBER
 *				: STATE s - ON | OFF
 * Return		: none...
 * Notes		: Updates 'active' an internal global variable.
 *
 */

void traffic_change (LIGHT w, STATE s)
{ 
	// -- process ................................................

		switch (w) {
		case RED	: 

			pRED = s; 
				if(s) LED_2_ON; else LED_2_OFF;
			break;
		case AMBER	: 
		
			pAMBER = s; 
				if(s) LED_3_ON; else LED_3_OFF;
			break;
		case GREEN	: 
		
			pGREEN = s;			
				if(s) LED_4_ON; else LED_4_OFF;
			
			break;

		case COMPLETE	:
			if(s) LED_1_ON; else LED_1_OFF;

		}
}

/* -- traffic_init --------------------------------------------------------
 *
 * Description	: Initializes the LED's on the ARM Evaluation board to be 
 *                OFF. Setup the internal GLOBALS to indicate that the 
 *                LED's are OFF.
 *
 * Parameters	: none...
 * Return		: none...
 * Notes		: none...
 *		  
 */

void traffic_init (void)
{
	// -- init internal ..........................................

	pRED   		= 0;
	pAMBER  	= 0;
	pGREEN 		= 0;

	// -- init hardware ..........................................
			
	traffic_change (RED, OFF);
	traffic_change (AMBER, OFF);
	traffic_change (GREEN, OFF);
	traffic_change (COMPLETE, OFF);

	irq_init ();
	timer_init();
	segment_init();
}

/* -- traffic_addone -----------------------------------------------------
 *
 * Description	: return an number incremented by 1
 *
 * Parameters	: int num - number passed into the function.
 * Return		: int
 * Notes		: an example of using in-line assembler.
 *
 */

int traffic_addone ( int num )
{
	__asm 
	{
	mov 		r0, num		// r0 = num
	add 		r0, r0, #1	// r0 = r0 + 1
	mov 		num, r0		// num = r0
	}
	
	return num;
}

/* -- traffic_sequence ------------------------------------------------
 *
 * Description	: Runs the traffic light sequence...
 *
 * Parameters	: int cycles - number of cycles 
 * Return		: none...
 * Notes		: none...
 *
 */


/****************************************************
 * USA Traffic Lights
 ****************************************************/

#ifndef EUROPEAN

void traffic_sequence (void)
{
	// -- init ...............................................................
	
	if ( cycles >= MAXCYCLES ) Exit();

	// -- USA Traffic Lights - Terminate 

	segment_set (phase);
	
	// -- process ............................................................
		
		switch (phase) {

		case 0		: // -- switch the GREEN(off) then AMBA(on) ...

			traffic_change 	(GREEN,OFF);
			traffic_change	(AMBER,ON);
			phase		= 1;
			break;	

		case 1		: // -- switch the AMBA(off) then RED(on) ....
		
			traffic_change  (AMBER, OFF);
			traffic_change	(RED,   ON);
			phase		= 2;			
			break;
		

		case 2		: // -- switch the RED(off) then GREEN(on) ...

			traffic_change 	(RED,OFF);
			traffic_change  (AMBER,OFF);
			traffic_change	(GREEN,ON);
			phase			= 0;
			cycles 			= traffic_addone (cycles);
			break;
		
		}

}

#else

/****************************************************
 * EUROPEAN Traffic Lights
 ****************************************************/


void traffic_sequence ( void )
{

	// -- init ...............................................................

	if ( cycles >= MAXCYCLES ) Exit();

	// -- European Traffic Lights - Terminate 
	
	segment_set (phase);
	
	// -- process ............................................................
		
		switch (phase) {

		case 0		: // -- switch the GREEN(off) then AMBA(on) ...

			traffic_change 	(GREEN,OFF);
			traffic_change	(AMBER,ON);
			phase		= 1;
			break;	

		case 1		: // -- switch the AMBA(off) then RED(on) ....
		
			traffic_change 	(AMBER,OFF);
			traffic_change	(RED,ON);
			phase		= 2;			
			break;


		case 2		: // -- switch the RED(on) then AMBER(on) ...

			traffic_change 	(AMBER,ON);
			phase 		= 3;
			break;

		case 3		: // -- switch the RED(off) then GREEN(on) ...

			traffic_change 	(RED,OFF);
			traffic_change  (AMBER,OFF);
			traffic_change	(GREEN,ON);
			phase		= 0;
			cycles = traffic_addone (cycles);
			break;
		
		}

}

#endif

/* -- traffic_interrupt ----------------------------------------------------
 *
 * Description	: The interrupt button has been pressed. Toggles D1 LED...
 *
 * Parameters	: none...
 * Return		: none...
 * Notes		: none...
 *
 */

void traffic_interrupt (void)
{
	if( toggle == 0 ) {
	traffic_change  (COMPLETE, ON);
	toggle = 1;
	} else {
	toggle = 0;
	traffic_change  (COMPLETE, OFF);
	}
}

/* -- traffic_writes --------------------------------------------------------
 *
 * Description	: write a string via the Angel SWI call WriteC
 *
 * Parameters	: const char *string - string to be written
 * Return		: none...
 * Notes		: none...
 *
 */

void traffic_writes (const char *string)
{ 
int pos = 0;

	  while (string[pos] != 0) WriteC(&string[pos++]);
}

/* -- traffic_start --- */

void traffic_start (void) 
{
	timer_start();
}

void traffic_idle (void) 
{
	do { } while (1); // -- endless loop for Multi-ICE
}

/* -- C_Entry --------------------------------------------------------------
 *
 * Description	: entry point for traffic lights
 * 
 * Parameters	: none...
 * Return		: return 1 if successful
 * Notes		: none...
 *
 */

int C_Entry ( void )
{	
	// -- initialize all internal structures .......................

	traffic_init ();
	traffic_start();
	
	// -- reset banner .............................................

	traffic_writes ("\n    -- Traffic Light Example Now Initialized \n");
	
#ifdef EUROPEAN
	traffic_writes ("    -- European Traffic Lights \n\n");
#else
	traffic_writes ("    -- USA Traffic Lights \n\n");
#endif
	
	traffic_writes ("\n    ********************************************* \n");
	traffic_writes ("    *** Remember to RESET the board after USE *** \n");
	traffic_writes ("    ********************************************* \n");

	// -- process ..................................................

	traffic_sequence ();

		// -- end banner ...............................................
	
	traffic_idle();
	
	// Should never get here...

	return 0;
}

/**************************************************************************
 * END OF traffic.c
 **************************************************************************/