/*
PLEX_1

Voltage monitoring, FET activation and LED Charlieplexing

Program to monitor a 12v battery
Uses a FET to drive a load
Switches the load off when volts reach minimum (10v) and activates LED6

Push-button triggers an interrupt at any time
This reveals the battery voltage via 5 LEDs
First LED represents 10v and each flash 0.1v
Second LED represents 11v, etc
Voltage is displayed 3 times

6 LEDs are driven from 3 ports using a technique called 'Charlieplexing'
Two ports are configured as Outputs and the high/low determines which LED glows
Ports not associated with the LED being activated are made Inputs
This makes them high impedance and effectively 'not there'

Written for PIC12F683 (8 pin) / BoostC compiler with SourceBoost IDE
Personal and non-commercial use encouraged
Copyright 2007 - David Theunissen - See www.flyelectric.ukgateway.net
*/

//PREPROCESSOR =================================================================

#include <system.h>			//Generic device include (actual device set in Settings/Target)

//Core configuration options:
#pragma DATA _CONFIG, _FCMEN_OFF & _IESO_OFF & _BOD_ON & _CPD_OFF & _CP_OFF & _MCLRE_OFF & _PWRTE_ON & _WDT_OFF & _INTOSCIO


//VARIABLES ====================================================================

#define plex1 gpio.0		//GP0 (pin7)	Charlieplex port 1
#define plex2 gpio.1		//GP1 (pin6)	Charlieplex port 2
#define plex3 gpio.2		//GP2 (pin5)	Charlieplex port 3
#define push gpio.3			//GP3 (pin4)	Push-button
#define fet gpio.5			//GP5 (pin2)	FET output

typedef unsigned char  u8;	//Defines u8 as an unsigned char type (8bits)
typedef unsigned short u16;	//Defines u16 as an unsigned short type (16bits)

u16	batt;					//Voltage of battery being monitored
bit	disp;					//Flag set in interrupt for displaying volts

//Functions declared and explained
void measure_battery();		//ADC function to measure 12v battery
void interrupt();			//Push-button triggers interrupt to reveal voltage via LEDs
void display_volts();		//Displays voltage via LEDs
void led1 (bit state);		//Enables individual LEDs... (state: 1=on; 0=off)
void led2 (bit state);
void led3 (bit state);
void led4 (bit state);
void led5 (bit state);
void led6 (bit state);
void eeprom_write();		//Writes test data to EEPROM


//FUNCTIONS ====================================================================

void interrupt()		//Interrupt function when push-button is pressed
{
	disp = 1;				//Set display flag
	intcon.0 = 0;			//GPIF: Clear interrupt bit to allow re-use
}

//-----------------------------------------------------------------------------

void measure_battery()	//Function to trigger ADC conversions to measure 12v battery
{
u8 i;		//Counter

//Run ADC
	for(i=0; i<1; i++);			//Delay for acquisition capacitor to u8ge (1 = ~14uS)
	pir1.6 = 0;					//Clear the ADC Complete flag
	adcon0.1 = 1;				//GO: Start ADC acquisition
	while(pir1.6==0);			//Wait for conversion to complete (become 1)
	
//Store ADC value in global variable 'batt'
	MAKESHORT(batt, adresl, adresh);
}

//-----------------------------------------------------------------------------

void display_volts()		//Function to display results via LEDs
{
	u8 i;			//Counter

//Flash LED1 once for each 0.1v above 10.0
//Code for first 'step' shown nicely below (all other steps closer together to save space)	
	if (batt>=656 && batt<662)		//If battery voltage is between 10.0 and 10.1v
	{
		for(i=0;i<1;i++)
		{
			led1(1); delay_ms(250);	//Flash LED1 once for each 0.1v
			led1(0);
		}
		delay_s(1);					//Pause between cycles (longer when LED flashes once only)
	}
	else if (batt>=662 && batt<669) {for(i=0;i<2;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=669 && batt<675) {for(i=0;i<3;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=675 && batt<682) {for(i=0;i<4;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=682 && batt<688) {for(i=0;i<5;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=688 && batt<695) {for(i=0;i<6;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=695 && batt<701) {for(i=0;i<7;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=701 && batt<708) {for(i=0;i<8;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=708 && batt<715) {for(i=0;i<9;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=715 && batt<721) {for(i=0;i<10;i++) {led1(1); delay_ms(250); led1(0); delay_ms(150);} delay_ms(250); delay_ms(250);}

//11.0 - 12.0	
	else if (batt>=721 && batt<728) {led2(1); delay_ms(250); led2(0); delay_s(1);}
	else if (batt>=728 && batt<734) {for(i=0;i<2;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=734 && batt<741) {for(i=0;i<3;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=741 && batt<747) {for(i=0;i<4;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=747 && batt<754) {for(i=0;i<5;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=754 && batt<760) {for(i=0;i<6;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=760 && batt<767) {for(i=0;i<7;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=767 && batt<774) {for(i=0;i<8;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=774 && batt<780) {for(i=0;i<9;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=780 && batt<787) {for(i=0;i<10;i++) {led2(1); delay_ms(250); led2(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	
//12.0 - 13.0
	else if (batt>=787 && batt<793) {led3(1); delay_ms(250); led3(0); delay_s(1);}
	else if (batt>=793 && batt<800) {for(i=0;i<2;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=800 && batt<806) {for(i=0;i<3;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=806 && batt<813) {for(i=0;i<4;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=813 && batt<819) {for(i=0;i<5;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=819 && batt<826) {for(i=0;i<6;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=826 && batt<833) {for(i=0;i<7;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=833 && batt<839) {for(i=0;i<8;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=839 && batt<846) {for(i=0;i<9;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=846 && batt<852) {for(i=0;i<10;i++) {led3(1); delay_ms(250); led3(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	
//13.0 - 14.0
	else if (batt>=852 && batt<859) {led4(1); delay_ms(250); led4(0); delay_s(1);}
	else if (batt>=859 && batt<865) {for(i=0;i<2;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=865 && batt<872) {for(i=0;i<3;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=872 && batt<878) {for(i=0;i<4;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=878 && batt<885) {for(i=0;i<5;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=885 && batt<892) {for(i=0;i<6;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=892 && batt<898) {for(i=0;i<7;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=898 && batt<905) {for(i=0;i<8;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=905 && batt<911) {for(i=0;i<9;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	else if (batt>=911 && batt<918) {for(i=0;i<10;i++) {led4(1); delay_ms(250); led4(0); delay_ms(150);} delay_ms(250); delay_ms(250);}
	
//>14.0
	else if (batt>=918) {led5(1); delay_ms(250); led5(0); delay_s(1);}
}
		
//------------------------------------------------------------------------------

void eeprom_write()			//Function to write to EEPROM flash memory
{
	intcon.7 = 0;				//Disable all interrupts while writing to memory
    pir1.7 = 0;					//EEIF: Clear this bit which gets set after each write
	
	eecon2 = 0x55;				//Required before writing to memory
	eecon2 = 0xAA;				//Required before writing to memory
	eecon1.1 = 1;				//WR: Writes data eedata to address eeadr

	while(eecon1.1==1);			//Wait for write to complete (becomes 0 when complete)

	eeadr++;					//Increment the address by 1 for next write (8 bit 0-255)
    intcon.7 = 1;				//Enable interrupts again
}

//------------------------------------------------------------------------------

void led1 (bit state)		//Function to enable or disable LED
{
	trisio.0 = 1;			//Set plex1 port as input to disable
	trisio.1 = 0;			//Set plex2 port as output
	trisio.2 = 0;			//Set plex3 port as output
	
	if (state==1)			//Switch LED on if so selected
	{
		plex2 = 0;
		plex3 = 1;
	}
	
	else					//Switch LED off
	{
		plex2 = 0;
		plex3 = 0;
	}
}

//------------------------------------------------------------------------------

void led2 (bit state)		//Function to enable or disable LED
{
	trisio.0 = 0;
	trisio.1 = 0;
	trisio.2 = 1;
	
	if (state==1)			//Switch LED on if so selected
	{
		plex1 = 0;
		plex2 = 1;
	}
	else					//Switch LED off
	{
		plex1 = 0;
		plex2 = 0;
	}
}

//------------------------------------------------------------------------------

void led3 (bit state)		//Function to enable or disable LED
{
	trisio.0 = 0;
	trisio.1 = 0;
	trisio.2 = 1;
	
	if (state==1)			//Switch LED on if so selected
	{
		plex1 = 1;
		plex2 = 0;
	}
	else					//Switch LED off
	{
		plex1 = 0;
		plex2 = 0;
	}
}

//------------------------------------------------------------------------------

void led4 (bit state)		//Function to enable or disable LED
{
	trisio.0 = 1;
	trisio.1 = 0;
	trisio.2 = 0;
	
	if (state==1)			//Switch LED on if so selected
	{
		plex2 = 1;
		plex3 = 0;
	}
	else					//Switch LED off
	{
		plex2 = 0;
		plex3 = 0;
	}
}

//------------------------------------------------------------------------------

void led5 (bit state)		//Function to enable or disable LED
{
	trisio.0 = 0;
	trisio.1 = 1;
	trisio.2 = 0;
	
	if (state==1)			//Switch LED on if so selected
	{
		plex3 = 1;
		plex1 = 0;
	}
	else					//Switch LED off
	{
		plex3 = 0;
		plex1 = 0;
	}
}

//------------------------------------------------------------------------------

void led6 (bit state)		//Function to enable or disable LED
{
	trisio.0 = 0;
	trisio.1 = 1;
	trisio.2 = 0;
	
	if (state==1)			//Switch LED on if so selected
	{
		plex1 = 1;
		plex3 = 0;
	}
	else					//Switch LED off
	{
		plex1 = 0;
		plex3 = 0;
	}
}

//==============================================================================

void main()
{
	gpio = 0;					//Initialise all ports low on startup
	
//Main port settings (1=Input 0=Output)
	trisio.0 = 1;				//Sets GP0/AN0 	(pin7) to INput to disable (plex1)
	trisio.1 = 1;				//Sets GP1/AN1 	(pin6) to INput to disable (plex2)
	trisio.2 = 1;				//sets GP2/AN2 	(pin5) to INput to disable (plex3)
	trisio.3 = 1;				//sets GP3	 	(pin4) to INput (Push-button)
	trisio.4 = 1;				//sets GP4/AN3 	(pin3) to INput (12v source)
	trisio.5 = 0;				//Sets GP5 		(pin2) to Output (FET)
    
//ADC port settings (1=Analog 0=Digital)
	ansel.0 = 0;				//Sets AN0 (pin7) to digital
	ansel.1 = 0;				//Sets AN1 (pin6) to digital
    ansel.2 = 0;				//Sets AN2 (pin5) to digital
    ansel.3 = 1;				//Sets AN3 (pin3) to analogue (12v battery)
    
    cmcon0 = 0b111;				//Switches all 3 comparator ports off
	
//Static ADC settings
    ansel.4 = 1;				//ADCS: Set AD Conversion Clock to Fosc/16
    ansel.5 = 0;				//part of above
    ansel.6 = 1;				//part of above
    pie1.6 = 0;					//ADC interrupts disabled
    adcon0 = 0b10001101;		//Makes AN3 channel active
	    
//Static Interrupt settings
    intcon.7 = 1;				//GIE: Enable interrupts globally
    intcon.3 = 1;				//GPIE: Enable GPIO interrupts
    ioc.3 = 1;					//Enable GP3 (pin4) only
/*
//Static EEPROM data logging settings
    eecon1.7 = 0;				//EEPGD: Access data memory
    eecon1.3 = 0;				//WRERR: clear on startup in case previously set
	eecon1.2 = 1;				//WREN: enable writing to memory
*/
//Flash LED's on startup
	led1(1); delay_ms(150); led1(0); delay_ms(50);
	led2(1); delay_ms(150); led2(0); delay_ms(50);
	led3(1); delay_ms(150); led3(0); delay_ms(50);
	led4(1); delay_ms(150); led4(0); delay_ms(50);
	led5(1); delay_ms(150); led5(0); delay_ms(50);
	led6(1); delay_ms(150); led6(0); delay_ms(50);

//------------------------------------------------------------------------------

	u8	i;			//Counter
	bit	mode;		//Status indicator
	mode = 1;		//1=Volts above min; 0=volts have been below min

	while(1)
	{
		measure_battery();		//Measure 12v battery voltage
		
		if (batt>=656 && mode==1) fet=1; //Activate FET if volts above minimum and not previously too low
		
		else
		{
			fet=0;				//Otherwise switch FET off
			mode=0;				//Set status to prevent FET from being switched on again
			led6(1);			//Activate warning LED
		}
		
		if (disp==1)			//'Display flag' set in interrupt
		{
			for (i=0; i<3; i++)
			{
				display_volts();//Display voltage three times
			}
			disp=0;				//Reset flag used in interrupt
		}
		
	}						//end while
}							//end main