/*
TEMP1
Temperature monitor and data logging

One to four temperature sensors can be used
Each are measured every second
The highest value for each is stored during a 5 second cycle and then written to memory
The LED is illuminated if any sensor exceeds 50'C (visual indication of high heat)

Memory is cleared every time the device is powered up
Data must start being downloaded before LED's stop flashing (within 6 seconds of applying power)
Memory can hold 32 iterations of 4 sensors
Measuring temperatures in 5 second 'cycles' yields 5 minutes recording time

Sensors can be calibrated by setting values in the 'offset' array
To get identical measurements:
	1. Comment out the 'Convert to degrees' section in measure_temp() (to get raw ADC values)
	2. Zero the values in the offset[] array
	3. Suspend sensors in still air and allow to settle
	4. Capture test data and adjust the offset[] array to give no differences
	5. Restore the commented out code

Written for PIC12F683 (8 pin) / BoostC compiler and MCP9701 temperature sensors
Assuming a 5v reference voltage, an ADC value of 82 represents 0'C
Each degree above or below this increments ADC value by 4 (eg: 282 is 50'C: 282-82 =200 /4 =50')

Personal and non-commercial use encouraged
Copyright 2007 - David Theunissen - See www.flyelectric.ukgateway.net
*/

//PREPROCESSOR section ========================================================

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

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

//VARIABLES section ===========================================================

#define led 	gpio.5			//GP5 (Pin2) is LED

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

u8	offset[5] = {0,11,0,0,0};	//Mechanism for calibrating sensors (ignore 1st)

u16 temp[5];					//Individual temperature sensor values
u16	high_t[5];					//Highest accummulated temperatures in each cycle
u16	highest_t;					//Highest overall temperature seen (for LED)

u16 t_value;					//Used to run ADC module
u8	channel[5];					//ADC channel config
u16 m_count;					//Memory counter - prevents over-writes


//FUNCTIONS section ===========================================================

void write_data ()			//Function to write to EEPROM flash memory
{
	intcon.7 = 0;				//Disable all interrupts if not done elsewhere
    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 if appropriate
}

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

void run_adc ()						//Function to run ADC conversions
{
    u8	p;
    
    //Run ADC
		for(p=0; p<1; p++);				//Delay for acquisition capacitor to charge (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 ADCVALUE
		MAKESHORT(t_value, adresl, adresh);
}
		
//-----------------------------------------------------------------------------

void measure_temp ()			//Function to trigger ADC conversions and measure temperatures
{
	u8	i;

//adcon0 structure...				//1  Right justify ADC values
    								//0  Use Vdd as reference
    								//00 Not used
	   								//10 Input channel (CHS0) is AN2 (THIS PART CHANGES BELOW)
    								//0  ADC capture (GO) not started
    								//1  ADC enabled

//Run ADC	
	for(i=1; i<5; i++)
	{
	    adcon0 = channel[i];		//Makes AN0 channel active
	    run_adc();					//Run ADC conversion
	    temp[i] = t_value;			//Copy result into appropriate register
	}

//Convert to degrees
	for(i=1; i<5; i++)
	{
		temp[i] -= offset[i];		//Deduct calibration value
		temp[i] -= 82;				//Deduct 0' offset
		temp[i] /= 4;				//Convert to degrees C
	}

}

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

void main()					//main program
{
//Main port settings
	gpio = 0;					//Initialise port
	
	trisio.0 = 1;				//Sets GP0/AN0 (pin7) to Input (sensor1)
	trisio.1 = 1;				//Sets GP1/AN1 (pin6) to Input (sensor2)
	trisio.2 = 1;				//sets GP2/AN2 (pin5) to Input (sensor3)
	trisio.4 = 1;				//sets GP4/AN3 (pin3) to INput (sensor4)
	trisio.5 = 0;				//Sets GP5 (pin2) to Output (LED)
    
	ansel.0 = 1;				//Sets AN0 (pin7) to analogue
	ansel.1 = 1;				//Sets AN1 (pin6) to analogue
    ansel.2 = 1;				//Sets AN2 (pin5) to analogue
    ansel.3 = 1;				//Sets AN3 (pin3) to analogue
    
    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
    
//ADC channel config
	channel[1] = 0b10000001;
	channel[2] = 0b10000101;
	channel[3] = 0b10001001;
	channel[4] = 0b10001101;
	
//Initialise
	u8	i;
	u8	k;

	highest_t = 0;
   	m_count = 0;
   	
//Static EEPROM data logging settings
    eecon1.3 = 0;				//WRERR: clear on startup in case previously set
	eecon1.2 = 1;				//WREN: enable writing to memory
    eeadr = 0;					//Address to be used for first write

//Flash LED three times on startup	
//Download of data must start in this 3sec window to avoid being over-written
	for (i=0; i<3; i++)
	{
		led=1;
		delay_s(1);
		led=0;
		delay_s(1);
	}

//Initialise EEPROM				//This overwrites memory so start download before LEDs stop flashing!!!
	u16	e;
	for (e=0; e<256; e++)
	{
		eedata = 0;
		write_data();
	}
    eeadr = 0;					//Address to be used for first write in rest of program
				
//-----------------------------------------------------------------------------

	while(1)
	{
	//Initialise	
		for(i=1; i<5; i++) high_t[i]=0;
	
	//Establish timing of cycles and writes to memory ('k' represents seconds)
		for (k=0; k<10; k++)			//Measure sensors k times in each cycle
		{
			measure_temp();				//Measure all sensors
			
			for(i=1; i<5; i++)
			{
				if(temp[i]>high_t[i]) high_t[i]=temp[i];//Store highest temperatures
			}
			delay_s(1);					//Wait 1 second
		}
		
	//Write highest temperatures in each cycle to memory
		if (m_count<252)	//Check if space remains (to prevent memory being over-written)
		{	
			for(i=1; i<5; i++)
			{
				eedata = high_t[i];		//Select high 8bits to record
				write_data();			//Write to memory
				m_count ++;				//Increment counter
			}
		}
			
	//Determine highest temperature seen
		for(i=1; i<5; i++)
		{
			if (high_t[i]>highest_t) highest_t=high_t[i];	//Increment if higher
		}
			
	//Illuminate LED if chosen threshold exceeded (simple visual indication)
		if (highest_t>50) led=1;	//One-off; does not reset
			
		
	}							//end while
}								//end main