//
// GFA BATTERY MONITOR
//
// version 1.0
//
// OKIRAKU AUDIO  2025-May

#include "12F615.H"
#device ADC=10
#fuses INTRC_IO,NOWDT,NOMCLR,BROWNOUT,PUT
#use delay(internal=4MHz)
#use fast_io(A)

#define		LED				PIN_A5		// LED
#define		SPEAKER_P		PIN_A1		// SPEAKER +
#define		SPEAKER_M		PIN_A2		// SPEAKER -
#define		POWER_MONITOR	(0)			// POWER MONITOR

#define		PIC_VOLT		(5.0)		// supply voltatge
#define		BAT_LOW			(6.9)		// battery low voltage
#define		BAT_BAD			(6.3)		// battery bad voltage
#define		VOLTAGE_DIV		(3.0) 		// ADC input 1/3 batteru voltage

//
// A/D function routine
//
int16 get_ad()		// BASIC A/D FUNCTION
{	int1	done; int16	value;
	read_adc(ADC_START_ONLY); done = adc_done();
	while(!done) done=adc_done();
	value=read_adc(ADC_READ_ONLY); return(value);
}

int16	get_ad4()
{
	int16	j;
	j=get_ad(); j+=get_ad();
	j+=get_ad(); j+=get_ad();
	return(j>>2);
}

void io_select()
{
	output_low(LED);
	output_drive(LED);
	output_low(SPEAKER_P);
	output_low(SPEAKER_M);
	output_drive(SPEAKER_P);
	output_drive(SPEAKER_M);
	setup_adc(ADC_CLOCK_DIV_16);
	setup_adc_ports(sAN0);				// Only AN0 A/D input
	set_adc_channel(POWER_MONITOR);
}

void beep(int16 n) // aprox. 4kHz
{
	while(n--){
		output_high(SPEAKER_P);
		output_low(SPEAKER_M);
		delay_us(120);
		output_high(SPEAKER_M);
		output_low(SPEAKER_P);
		delay_us(120);
	}
	output_low(SPEAKER_P);
	output_low(SPEAKER_M);
}

main()
{
	int16 batv;

	io_select();
	delay_ms(100);

	while(1){
		batv = get_ad4();
		if(batv > (int16)(BAT_LOW/VOLTAGE_DIV/PIC_VOLT*1024.0)){ // NORMAL
			output_low(LED);
		}
		else if(batv > (int16)(BAT_BAD/VOLTAGE_DIV/PIC_VOLT*1024.0)){ // LOW
			output_high(LED);
		}
		else { // BAD
			output_high(LED);
			beep(800);
			output_low(LED);
			delay_ms(300);
		}
	}
}

// end of program