//	lab5c_la.c
//	May 2010  Leo Altmann <laltmann@hmc.edu>
//	C implementation of Lab 5 for PIC32
//  Oct 2014 Modified by Josef Spjut <jspjut@g.hmc.edu>

//	Include
#include <P32xxxx.h>

#include "notes.h"
#include "prototypes.h"

void main(void) 
{
	int note = 0;
	unsigned short period, duration;
	
	TRISF = 0;		// Use PORTF for output
	initTimers();	// Set up Timer0 and Timer1
	
	while (1) {
		period = notes[note*2];
		duration = notes[(note*2)+1];
		
		if (duration == 0) break;
		playNote(period, duration);
		note++;
	}
}

void initTimers(void) {
	
	//	Assumes peripheral clock at 5MHz
	
	// 	Use Timer1 for note duration
	//	T1CON
	//	bit 15: ON=1: enable timer
	//	bit 14: FRZ=0: keep running in exception mode
	//	bit 13: SIDL = 0: keep running in idle mode
	//	bit 12: TWDIS=1: ignore writes until current write completes
	//	bit 11: TWIP=0: don't care in synchronous mode
	//	bit 10-8: unused
	//	bit 7:	TGATE=0: disable gated accumulation
	//	bit 6:	unused
	//	bit 5-4: TCKPS=11: 1:256 prescaler
	//	bit 3:	unused
	//	bit 2:	don't care in internal clock mode
	// 	bit 1:	TCS=0: use internal peripheral clock
	//	bit 0:	unused
	T1CON = 0b1001000000110000;

	//	Use Timer2 for frequency generation	
	//	T2CON
	//	bit 15: ON=1: enable timer
	//	bit 14: FRZ=0: keep running in exception mode
	//	bit 13: SIDL = 0: keep running in idle mode
	//	bit 12-8: unused
	//	bit 7: 	TGATE=0: disable gated accumulation
	//	bit 6-4: TCKPS=010: 1:4 prescaler
	//	bit	3:	T32=0: 16-bit timer
	//	bit 2:	unused
	//	bit 1:	TCS=0: use internal peripheral clock
	//	bit 0:	unused
	T2CON = 0b1000000000100000;
}

void playNote(unsigned short period, unsigned short duration) {
	
	TMR1 = 0;	// Reset timers
	TMR2 = 0;
	
	
	while (TMR1 < duration) {	// Play until note ends
		if (period != 0) {		// Not a rest, so oscillate
			PORTFbits.RF0 = 0;	// Output low
			TMR2 = 0;
			while (TMR2 < period) {}	// wait
			PORTFbits.RF0 = 1;	// Output high
			TMR2 = 0;
			while (TMR2 < period) {}	// wait
		}
	}
}