/*******************
 * Universidade Federal de Campina Grande
 * Disciplina: 
 *
 * 
 *  Hugo Raniere
 *  Michael Angelo
 *
 */

#include <MC68HC908QY4.h> /* include peripheral declarations */
#include <hidef.h>

void main(void) {
	
    int soma = 0;
    int i = 0;
	int modulo = 0;
	
    PTA = 0; /* clear/initialize Port A */

    /* do PWM */
    TSC_TSTOP = 1; // stop counter
    TSC_PS = 0;    // prescaler divide por 1
    TSC_TRST = 1;  // reset counter 
    TMODH =  0; TMODL = 250; // PWM frequency 20kHz
    TCH1H =  0; TCH1L =  50; // pulse width 
    TSC0_MS0B  = 0;  // PWM 
    TSC1_MS1A  = 1;  // output compare 
    TSC1_ELS1B = 1; TSC1_ELS1A = 0;  // clear on compare
    TSC1_TOV1  = 1;  // toggle on overflow
    TSC_TSTOP = 0;   // start counter

    /* do AD */
    ADSCR_CH = 2;     // entrada pino AD2=PTA4
    ADSCR_ADCO = 1;   // convert continously
    ADICLK_ADIV = 2;  // AD clock = 5MHz/4 (about 1MHz)
    

  	TCH1L = 5;

	/* 5 <= TCH1L <= 230 */
	
    for(;;) {
      	soma = 0;
      	i = 0;
      	
      	while (i < 20) { // 1 milisegundo
      	
			while(!PTA_PTA1);
		 	
			modulo = (ADR < 124) ? (124 - ADR) : (ADR - 124);
			soma += modulo;
	
			while(PTA_PTA1);			
			
			i++;
		}
		
		if (soma > 400) {
			
			if (TCH1L == 5)
				TCH1L = 230;
			else 
				TCH1L = 5;
				
			// espera 1 segundo
			for (i = 0; i < 20000; i++) {
				while(!PTA_PTA1);
				while(PTA_PTA1);
			}
		}	
    }
}