;PROGRAMMING OPTIONS************************************************
;
; When programming the PIC 16f88 using the Assembler (ASM:IDE), the following options are selected:
;
; Oscillator selection; EXTRC as clock-out
;Watchdog timer - disabled
; Power up timer - disabled
; Pin function select; MCLR
; Brown-out protection - enabled
; Code Proection - diabled
;Low Voltage program - enabled
; data EE read protect - disabled
;Flash program write enable: Write protect - disabled
;Background debug - disabled
;CCP1 Mux pin; RB0
;code proect - disabled
;fail-safe clock monitor - enabled
;internal/eternal switch over mode - enabled
;
;I/O ALLOCATION*****************************************************
;
;INPUTS...........................................................
;
;Analogue sensors (input)	AN4-AN6(VDD = 5.0V)	; There is only going to be one temperature sensor to be used through one of these pins, the reason why three have been selected is for other sensors to be added after the temperature sensor has been tried and tested successfully
;Digital I/O 		RA0-RA3 		
;
;OUPUTS...........................................................
;
; LED
;
;PORT DATA DIRECTION CODES REQUIRED...............................;
;
;
;ADC SETUP********************************************************
;
;ANSEL	bit	7	0= unimplimated
;	bits	6543	1= analog input
;	bits 	210	0= digital I/O
;
;ANSEL = 01111000	
;
;ADCON1	bit	7	1= right justify result in ADESH/scriptDRESL
;	bit	6	0= disabled (not needed)
;	bits	54	10== VREF-VSS
;	bits	3210	0= unimplemented
;
;ADCON1 = 1010000
;
;ADCON0 	bits	76	0= A/D clock = f/8
;	bits 	543	channel select (AN0-AN7)
;	bit	2	GO=1/DONE=0
;	bit	0	A/D Module enable = 1
;
;ADCON0 = 01111001
;
;	Create  list file and select processor :
	list p = 16f88
;
#DEFINE	PAGE0 BCF STATUS,5
#DEFINE	PAGE1 BSF STATUS,5
;
;	Include file containing register labels:
	Include "p16f88.inc"
;
STATUS	EQU H'03'	; STATUS register
count 	EQU 020		; assign General Purpose Register, Bank 0 for counter 
z	EQU 2		;Zero flag
;
;set origin at address 000
org	0x000

				
	ORG	0		; Reset vector
	GOTO	5		; Goto start of program
	ORG	4		; Interrupt vector
	GOTO	5		; Goto start of program
	ORG	5		; Start of program memory

	; set up code for 16F88 ports
	BSF	3,5	;switch to page 1
	CLRF	H'9b'	;clear ansel file - set ports to digital io
	BCF 	3,5	;switch to page 0
;
;SETUP STATUS REGISTER............................................
;

;
;SETUP ADC........................................................
;
	banksel	ANSEL		;select register bank
	movlw	b'01111000'	
	movwf	ANSEL		;write A/D control word
;
	banksel	ADCON1		;select register bank
	movlw	b'10100000'	
	movwf	ADCON1		;write A/D control word
;
	banksel	ADCON0		;select register bank
	movlw	b'01111001'
	movwf	ADCON0		;write A/D control word
;
;SUBROUTINE TO WAIT ABOUT 0.8MS..................................
;
delay	movlw	256		;load time delay of 256x3=768
	movwf	count		;load counter	down	decfsz	count		;decrement and test counter
	goto 	count
;
;SUBROUTINE TO GET ANALOGU INPUT - 20US SETTLING TIME.............
;
A2D	movlw	007		;time delay of 7x3=21us
	movwf	count		;load counter
again	decfsz	count		;decrement until zero
	goto 	again		;decrement until zero
;
;GET ANALOGUE INPUT..............................................
;
	movlw	b'01000001'
	movwf	ADCON0
adc	bsf	ADCON0, GO	;start a2d conversion
wait	btfsc	ADCON0, GO	;wait for conversion to complete
	goto 	wait
	movf	ADRESL, h'08'	;place in register location for testing
	movf	ADRESH,	h'09'	;place in register loaction for testing
;
	movlw	H'66'		;place the total of 614-bits
	movwf	h'35'		;in two empty locations of memory bank 0
	movlw	H'02'		;these are to test the thermistor component
	movwf	H'36'		;to see if it is >60% of it's original value
;	
	movf	H'35', w		
	subwf	H'08', H'08'	;subtract loaded ADC value from 102-bytes and place into memory
	movf	H'36', w
	subwf	H'09', H'09'	;subtract loaded ADC value from 2-bytes and palce into memory
;
	btfsc	h'08', z	;and test ADRESL...
	goto 	part2
	movlw	H'0F'		;...if the thermistor is >60% of it's original value, place the value 0F...
	movwf	H'4B'		;...into an empty register
;
part2	btfsc	H'09', z	;and then test ADRESH...
	goto	adc
	movlw	H'0F'		;...if the thermistor is >60% of it's original value, place the value 0F...
	movwf	H'4A'		;...into an empty register
;
;TEST TO SEE IF BOTH ADRESL AND ADRESH ARE BOTH POSITIVE.................
;
	movf	H'4A', w	;load the value of ADRESH into the working register
	ADDWF	H'4B', H'4A'	;add both ADRESH's and ADRESL's positive 'flags' (the values of 0F for both results), which would make the value of H'1E'
	btfss	H'4A', H'1E'	;...and test to see if this result is positive
	goto	adc
	goto	ledop		;if it is; turn on LED RB0
;
;
;
;LED OUTPUT IF THERMISTOR READS 61% OF ITS MAXIMUM VALUE..........
;
ledop 	CLRF	6		; set all Port B pins to logic 0 
 	BSF	3,5		; instruct program that a Page 1   
		 	 	; command comes next 
 	CLRF	6		; set all Port B pins as outputs 
 	BCF	3,5		; instruct program that a Page 0   
		 	 	; command comes next 
 	BSF	6,0		; set Port B pin 0 to logic 
	goto	adc		;keep testing and provide outputs as per programme parameters

	end