temperature sensors

This is a discussion on temperature sensors within the C Programming forums, part of the General Programming Boards category; Hi everyone, I've patched up a circuit. Connected a sensor to a PIC184520. Is it possible to write a program, ...

  1. #1
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    temperature sensors

    Hi everyone,

    I've patched up a circuit. Connected a sensor to a PIC184520. Is it possible to write a program, that the sensor can read stuffs and than I can watch it on my computer?

    Sorry for the bother, Thanks alot!

  2. #2
    and the hat of wrongness Salem's Avatar
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    Of course it's possible.
    The rest is down to you and your skill levels.

    A similar application found rather too easily via a search engine.
    http://forum.microchip.com/tm.aspx?m=240614
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
    {Jaxom,Imriel,Liam}'s Dad Kennedy's Avatar
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    Be sure that you get the conversion factors right for the type of thermocouple you are using. The differences between J and K, for example, can put you off several degrees.

  4. #4
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    Salem > I tried searching the search engines for similar codes, but most of them provided is using assembly language. I've only been taught C at sort of a beginners level, I do not understand assembly codes.

    Kennedy > The conversion factors can be found at the data sheet of the thermocouple? or I have to figure it myself slowly

    thank you thank you!

  5. #5
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    Prior to that, I have found some codes on the internet earlier on, exactly the same function as what i'm looking for as they state, but it is in assembly language. Possible to convert it to C?

  6. #6
    Deathray Engineer MacGyver's Avatar
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    If you don't understand assembly, then you can't port it to C.

  7. #7
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    I suddenly hate school. They straight away thought me C programming, they said assembly language was kinda obsolete, So I really have no idea.

    But the conversion from assembly to C is possible?

  8. #8
    Deathray Engineer MacGyver's Avatar
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    IMO you should learn C before Assembly.

    Is manul conversion possible? Yes.

  9. #9
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    Mac, sorry for the trouble anywhere to learn Assembly fast? I'm really desperate. My C is also not that good, just alot of basic stuffs that i know.


    I found this code. Everything is good, just ignore the photocell part.

    [tag]
    Code:
    ;------------------------------------------------------------------------------------------------------------------------
    ; Source code for the PIC16F873 based Digital Light and Temp. Reader.
    ;------------------------------------------------------------------------------------------------------------------------
    ;	
    ;	**Analog Pinouts
    ;	Analog Voltage Input	-	RA0 (Temp), RA1 (Light).
    ;	Low Voltage Reference	- 	Vss
    ;	High Voltage Reference	-	RA3, 2.56V
    ;	Resolution = 2.56V / 1024 = 2.5mV / bit.
    ;
    ;	**USART Pinouts
    ;	Transmit Data			- RC6 (TX)
    ;
    ;	**Modes
    ;	Debug Mode				- RC4 (Low = Debug, High = User)
    ;	Infra Mode				- RC5 (Low = Enabled, High = Disabled)
    ;
    ;	**LCD Pinouts
    ;	1	Vss -	Ground, 3rd pin of the potentiometer
    ;  	2	Vcc	-	5V DC, 1st pin of the potentiometer
    ;  	3 	Vee	-	Middle pin of the potentiometer
    ;  	4 	RS	-	RC0		(Data - 1, Instruction - 0)
    ;  	5 	R/W	-	RC1		(R - 1, W - 0)
    ;	6 	E	-	RC2		(Enable Pulse)
    ;	7 	DB0	-	RB0		(LSB)
    ;	8 	DB1	-	RB1
    ;	9 	DB2	-	RB2
    ; 	10	DB3	-	RB3		(Lower 4 bits)
    ; 	11	DB4 -	RB4		(Upper 4 bits)
    ; 	12	DB5	-	RB5
    ; 	13	DB6	-	RB6
    ; 	14	DB7	-	RB7		(MSB)
    ;
    ;	Instruction Cycle Time = 1 / (4MHz / 4) = 1us per instruction
    ;------------------------------------------------------------------------------------------------------------------------
    
    		LIST P=16F873
    		INCLUDE "p16f873.inc"   
    ;		ERRORLEVEL -302        
    		__CONFIG _PWRTE_OFF & _HS_OSC & _WDT_OFF & _WRT_ENABLE_ON & _LVP_OFF & _BODEN_OFF;  configuration switches
    
    			CBlock 0x20
    			N 					; Delay registers.
    			FIXDELAY		
    			visdelay
    			dataL
    
    			rmng_num			; Digit breaker registers.
    			quotient
    			temp_num
    
    			tempL				; Temp. variable registers.
    			tempH
    			tempCfract
    
    			digittempdata0		; Temp Data digit registers.
    			digittempdata1
    			digittempdata2
    			digittempdataL0
    			digittempdataL1
    			digittempdataL2
    
    			tempnonfract0		; Actual temperature digit registers.
    			tempnonfract1
    			tempnonfract2
    			tempfract0
    			tempfract1
    
    			briteL				; Brightness variable registers.
    			briteH
    			britefract
    
    			digitbritedata0		; Brightness data digit registers.
    			digitbritedata1
    			digitbritedata2
    			digitbritedataL0
    			digitbritedataL1
    			digitbritedataL2
    
    			britenonfract0		; Actual temperature digit registers.
    			britenonfract1
    			britenonfract2
    			britefract0
    			britefract1
    
    			tempHtrans			; Data to be passed to PC.
    			tempLtrans
    			briteHtrans
    			briteLtrans
    			ENDC
    
    			org 0x00
    			nop					; Reserved for ICD II.
    			goto start
    
    start 		call initports		; Initialize Ports as output/inputs.
    			call setupUART		; Setup USART.
    			call delay			; Delay for USART settling time.
    			call INITLCD		; Initialize LCD.
    
    main		call tempconv		; Convert temperature readings.
    			call briteconv		; Convert brightness readings.
    			call passdata2pc	; Pass data to PC.
    			call displaydata	; Display the calculated data, either in Debug or User mode.
    			call visualdelay	; Visual delay for the to view data.
    						
    			goto main
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Subroutine to initialize the PORTs as Inputs or Outputs.
    ;------------------------------------------------------------------------------------------------------------------------		
    
    initports
    			clrf PORTB
    			clrf PORTC
    
    			banksel TRISB		; All PORTB pins as output.
    			movlw b'00000000'
    			movwf TRISB
    
    			banksel TRISC		; Pins RC0-RC3 and RC6 as output. 
    			movlw b'10110000'	; Pins RC4-RC5 and RC7 as input.
    			movwf TRISC
    
    			return		
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Initialize the LCD.
    ;------------------------------------------------------------------------------------------------------------------------
    
    INITLCD		
    			BANKSEL PORTB		; Select Bank for PORTB.
    
    			MOVLW	0xE6		; Call for 46ms delay
    			CALL 	NDELAY		; Wait for VCC of the LCD to reach 5V
    			
    			BCF		PORTC, 0	; Clear RS to select Instruction Reg.
    			BCF		PORTC, 1	; Clear R/W to write
    		
    			MOVLW	B'00111011'	; Function Set to 8 bits, 2 lines and 5x7 dot matrix
    			MOVWF 	PORTB
    			CALL	ENABLEPULSE
    			CALL	DELAY50
    			CALL	ENABLEPULSE
    			CALL	DELAY50
    			CALL	ENABLEPULSE
    			CALL	DELAY50		; Call 50us delay and wait for instruction completion
    
    			MOVLW	B'00001000'	; Display OFF
    			MOVWF	PORTB
    			CALL	ENABLEPULSE
    			CALL	DELAY50		; Call 50us delay and wait for instruction completion
    
    			MOVLW	B'00000001'	; Clear Display
    			MOVWF	PORTB
    			CALL	ENABLEPULSE
    			MOVLW	0x09		; Call 1.8ms delay and wait for instruction completion				
    			CALL	NDELAY		
    
    			MOVLW	B'00000010'	; Cursor Home
    			MOVWF	PORTB
    			CALL	ENABLEPULSE
    			MOVLW	0x09		; Call 1.8ms delay and wait for instruction completion				
    			CALL	NDELAY
    		
    			MOVLW	B'00001100'	; Display ON, Cursor OFF, Blinking OFF
    			MOVWF	PORTB
    			CALL	ENABLEPULSE
    			CALL	DELAY50		; Call 50us delay and wait for instruction completion
    
    			MOVLW 	B'00000110'	; Entry Mode Set, Increment & No display shift
    			MOVWF	PORTB
    			CALL	ENABLEPULSE
    			CALL	DELAY50		; Call 50us delay and wait for instruction completion
    
    			BSF		PORTC, 0	; Set RS to select Data Reg.
    			BCF		PORTC, 1	; Clear R/W to write
    
    			RETURN
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Enable Pulse for writing or reading instructions or data
    ;------------------------------------------------------------------------------------------------------------------------
    
    ENABLEPULSE	BCF	PORTC, 2		; 2us LOW followed by 3us HIGH Enable Pulse and 2us LOW.
    			NOP
    			NOP
    			BSF	PORTC, 2
    			NOP
    			NOP
    			NOP
    			BCF PORTC, 2
    			NOP
    			NOP
    			RETURN
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; N DELAY SUBROUTINE, delay in multiples of 200us up to 200us*255 = 51ms (or more)
    ;------------------------------------------------------------------------------------------------------------------------
    
    NDELAY
    			MOVWF N				; N is delay multiplier
    NOTOVER		CALL DELAY200		; Call for 200us
    			DECFSZ N, 1			; Decrease N by 1
    			GOTO NOTOVER		; The delay isn't done
    			RETURN
    	
    ;------------------------------------------------------------------------------------------------------------------------
    ; FIXED 200us DELAY (Possibly more due to execution time of the DECFSZ instruction.)
    ;------------------------------------------------------------------------------------------------------------------------
    
    DELAY200	
    			MOVLW 0x42			; 66 LOOPS
    			MOVWF FIXDELAY		; 200us fixed delay
    NOTDONE200	DECFSZ FIXDELAY, 1 	; Decrement of FIXDELAY
    			GOTO NOTDONE200		; If 200us isn't up go back to NOTDONE200
    			RETURN				; If 200us is up then return to instruction.
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; FIXED 50us DELAY (Possibly more due to execution time of the DECFSZ instruction.)
    ;------------------------------------------------------------------------------------------------------------------------
    
    DELAY50	
    			MOVLW 0x10			; 16 LOOPS
    			MOVWF FIXDELAY		; 50us fixed delay
    NOTDONE50	DECFSZ FIXDELAY, 1 	; Decrement of FIXDELAY
    			GOTO NOTDONE50		; If 50us isn't up go back to NOTDONE50
    			RETURN				; If 50us is up then return to instruction.
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Visual delay subroutine.
    ;------------------------------------------------------------------------------------------------------------------------
    
    visualdelay movlw 0x12
    			movwf visdelay
    
    seetemp		movlw 0xFF
    			call NDELAY
    			decfsz visdelay, 1
    			goto seetemp
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Fast Directive to write characters to LCD.
    ;------------------------------------------------------------------------------------------------------------------------
    
    PUTCHAR
    			MOVWF PORTB			; A quicker way of writing characters to LCD.
    			CALL ENABLEPULSE
    			CALL CHKBUSY
    			RETURN
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Subroutine to check for the BUSY flag. Mostly used for instructions that follows up a character write.
    ;------------------------------------------------------------------------------------------------------------------------
    
    CHKBUSY
    			bcf	PORTC, 0		; Clear RS to select Instruction Reg.
    			bsf	PORTC, 1		; Set R/W to read.
    
    			banksel TRISB		; Select Bank for TRISC.
    			movlw 0xFF			; Define all PORTC Pins as Inputs.
    			movwf TRISB
    
    			banksel PORTC		; Select Bank for PORTC.
    			bsf PORTC, 2		; I tried to write my own code for this part initially but I wasn't successful.
    			movf PORTB, w		; Therefore, I implemented a portion of Peter Ouwehand's LCD Code.
    			bcf PORTC, 2		; Will look more into the BUSY flag of the LCD.
    			andlw 0x80			; Credits to Peter Ouwehand for his code here. :)
    			btfss STATUS, Z
    			goto CHKBUSY
    
    			banksel TRISB		; Select Bank for TRISB.
    			movlw 0x00			; Define all PORTC Pins as Outputs.
    			movwf TRISB
    		
    			banksel PORTC		; Select Bank for PORTA, B, and C.
    			bsf PORTC, 0		; Set RS to select Data Register.
    			bcf PORTC, 1		; Clear R/W to write.
    			
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Position Cursor to the next line.
    ;------------------------------------------------------------------------------------------------------------------------
    
    nextline
    			banksel PORTC
    			bcf PORTC, 0	; Select Instructions Register.
    			bcf PORTC, 1	; Select Write.
    
    			movlw b'11000000'	; Shift cursor to second line at 0x40 RAM address on LCD.
    			call PUTCHAR
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Clear screen and Cursor home.
    ;------------------------------------------------------------------------------------------------------------------------
    
    clrscreen
    			banksel PORTC
    			bcf PORTC, 0		; Clear RS to select Instructions Register.
    			bcf PORTC, 1		; Clear R/W to select Write.
    
    			banksel PORTB
    			MOVLW B'00000001'	; Clear Display
    			call PUTCHAR
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Position Cursor to home position.
    ;------------------------------------------------------------------------------------------------------------------------
    
    cursorhome
    			banksel PORTC
    			bcf PORTC, 0	; Select Instructions Register.
    			bcf PORTC, 1	; Select Write.
    
    			movlw b'00000010'	; Position cursor to home position.
    			call PUTCHAR
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Initialize ADC Subroutine
    ;------------------------------------------------------------------------------------------------------------------------
    		
    initadc		
    			banksel TRISA		; Select Bank for TRISA.
    			movlw b'00111111'	; Initialize RA0 - RA5 as Inputs.
    			movwf TRISA
    
    			banksel ADCON1		; Select Bank for ADCON1.
    			movlw b'00000101'	; ADFM for Left Justified, Vref-=Vss Vref+=AN3 Analog In=AN0, AN1 (R/C = 1/2).
    			movwf ADCON1
    
    			banksel ADCON0		; Select Bank for ADCON0.
    			movlw b'01000001'	; Fosc/8, Channel 0, Enable the ADC (Default Chan. 0)
    			movwf ADCON0		
    			
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Wait 20us for Acquisition time in order for holding capacitor to charge up.
    ;------------------------------------------------------------------------------------------------------------------------
    
    delay20		
    			banksel FIXDELAY	; A loop to generate 20us delay.
    			movlw 0x0A
    			movwf FIXDELAY
    			
    notdone20	decfsz FIXDELAY, 1 
    			goto notdone20
    			
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; This routine starts the AD Conversion and waits for it to complete.
    ;------------------------------------------------------------------------------------------------------------------------
    
    startadc	
    			banksel ADCON0		; Select Bank for ADCON0.
    			bsf ADCON0, GO		; Set the GO bit to begin AD Conversion.
    			
    			banksel ADCON0		; Select Bank for ADCON0.
    checkdone	btfsc ADCON0, GO	; Check if the conversion is done?
    			goto checkdone		; If not, check again.
    
    			return				; Else, return to the main programme.
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Subroutine to setup the USART.
    ;------------------------------------------------------------------------------------------------------------------------
    
    setupUART
    			banksel SPBRG			; Load into SPBRG the value of 103 for Baud Rate of 2400 with error of 0.17%.
    			movlw d'103'
    			movwf SPBRG
    
    			movlw b'00100100'		; Set 8 bit Transmission, Enable Transmit, Asynchronous Mode, High Speed.
    			movwf TXSTA
    
    			banksel RCSTA
    			movlw b'10010000'		; Enable Serial Port, 8 bit Reception, Enable Continuous Receive.
    			movwf RCSTA
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Delay to provide some settling time for start up.
    ;------------------------------------------------------------------------------------------------------------------------
    
    delay		
    			banksel dataL
    			clrf dataL
    
    settle		decfsz dataL, f			; The delay loop.
    			goto settle				
    
    			movf RCREG, w			; Flush the receive buffer.
    			movf RCREG, w
    			movf RCREG, w
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Receive character from RS232 and store in WREG.
    ;------------------------------------------------------------------------------------------------------------------------
    
    receive
    			banksel PIR1
    waitrcv		btfss PIR1, RCIF		; Wait for RCIF to be set, when set then receive buffur is full.
    			goto waitrcv			; If not set, then keep waiting.
    			movf RCREG, w			; If set, move buffer content to WREG.
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Transmit the character that is on WREG to RS232 and wait until the sending is complete.
    ;------------------------------------------------------------------------------------------------------------------------
    
    transmit
    			banksel TXREG
    			movwf TXREG				; Move character to TXREG to be transmitted.
    
    			banksel TXSTA
    waittrn		btfss TXSTA, TRMT		; Check if buffer is empty.
    			goto waittrn			; If no, then keep waiting.
    			banksel PORTB			; If yes, select Bank 0 and return.
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Select Channel AN0 of A/D Converter.
    ;------------------------------------------------------------------------------------------------------------------------
    
    chan0		
    			banksel ADCON0
    			bcf ADCON0, 5
    			bcf ADCON0, 4
    			bcf ADCON0, 3
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Select Channel AN1 of A/D Converter.
    ;------------------------------------------------------------------------------------------------------------------------
    
    chan1		
    			banksel ADCON0
    			bcf ADCON0, 5
    			bcf ADCON0, 4
    			bsf ADCON0, 3
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Breaks down a number to its individual digits.
    ;------------------------------------------------------------------------------------------------------------------------
    
    get_dig
    			movlw d'10'			; To split the digits, divide them by 10.
    			incf quotient, f	; Increment of quotient with each subtraction by 10.
    			subwf rmng_num, f	; Subtract the number by 10.
    			skpnc				; If already negative, stop division.
    			goto get_dig		; Else, continue dividing.
    			addwf rmng_num, f	; Restore number.
    			decf quotient, f	; Restore quotient.
    
    			movf rmng_num, w	; Move rmng_num to temp_num.
    			movwf temp_num
    			movf quotient, w	; Move quotient to rmng_num.
    			movwf rmng_num
    			movf temp_num, w
    
    			return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Temperature Conversion Subroutine.
    ;------------------------------------------------------------------------------------------------------------------------
    
    tempconv
    			call initadc		; Initialize and begin ADC on AN0.
    			call chan0
    			call delay20		; Delay to charge up holding capacitor.
    			call startadc		; Start ADC and await the completion.
    
    			banksel ADRESH		; Pass high byte to tempH.
    			movf ADRESH, w
    			movwf tempH
    			movwf tempHtrans
    
    			banksel ADRESL		; Pass low byte to tempL.
    			movf ADRESL, w
    			banksel tempL
    			movwf tempL
    			movwf tempLtrans
    
    arrgtemp	bcf STATUS, C		; Rearrange tempL from xx00 0000 to 0000 00xx.
    			rlf tempL, f
    			btfss STATUS, C
    			goto $+2
    			bsf tempL, 0
    
    			bcf STATUS, C
    			rlf tempL, f
    			btfss STATUS, C
    			goto $+2
    			bsf tempL, 0
    
    brkdigtemp	
    			banksel tempH
    			movf tempH, w
    			movwf rmng_num
    
    			clrf quotient			; Break ADC high byte result to individual digits to be displayed.
    			call get_dig
    			movwf digittempdata0
    
    			clrf quotient
    			call get_dig
    			movwf digittempdata1
    
    			clrf quotient
    			call get_dig
    			movwf digittempdata2
    
    			banksel tempL
    			movf tempL, w
    			movwf rmng_num
    
    			clrf quotient			; Break ADC low byte result to individual digits to be displayed.
    			call get_dig
    			movwf digittempdataL0
    
    			clrf quotient
    			call get_dig
    			movwf digittempdataL1
    
    			clrf quotient
    			call get_dig
    			movwf digittempdataL2
    
    calctempC					
    				banksel tempL
    				movlw d'25'				; Assign multiplier and clear fractional temperature reading.
    				clrf tempCfract
    
    mult25			addwf tempCfract, f		; Multiply ADRESL by 25 to obtain fractional temperature reading.
    				decfsz tempL, f
    				goto mult25
    
    breaktempC		movf tempH, w			; Break up temperature readings to ind. digits to be displayed.
    				movwf rmng_num			
    
    				clrf quotient
    				call get_dig
    				movwf tempnonfract0
    
    				clrf quotient
    				call get_dig
    				movwf tempnonfract1
    
    				clrf quotient
    				call get_dig
    				movwf tempnonfract2
    
    				movf tempCfract, w
    				movwf rmng_num
    
    				clrf quotient
    				call get_dig
    				movwf tempfract0
    
    				clrf quotient
    				call get_dig
    				movwf tempfract1
    
    				return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Brightness Conversion Subroutine.
    ;------------------------------------------------------------------------------------------------------------------------
    
    briteconv
    			call initadc		; Initialize and begin ADC on AN1.
    			call chan1
    			call delay20		; Delay to charge up holding capacitor.
    			call delay20
    			call startadc		; Start ADC and await the completion.
    
    			banksel ADRESH		; Pass high byte to briteH.
    			movf ADRESH, w
    			movwf briteH
    			movwf briteHtrans
    
    			banksel ADRESL		; Pass low byte to briteL.
    			movf ADRESL, w
    			banksel briteL
    			movwf briteL
    			movwf briteLtrans
    
    arrgbrite	bcf STATUS, C		; Rearrange briteL from xx00 0000 to 0000 00xx.
    			rlf briteL, f
    			btfss STATUS, C
    			goto $+2
    			bsf briteL, 0
    
    			bcf STATUS, C
    			rlf briteL, f
    			btfss STATUS, C
    			goto $+2
    			bsf briteL, 0
    
    			bcf STATUS, C		; Pass LSbit of briteH to 2nd bit of briteL.
    			rrf briteH, f
    			btfss STATUS, C
    			goto $+2
    			bsf briteL, 2
    
    chkbrite	movlw d'30'			; Check if brightness is below 30%.
    			subwf briteH, w		
    			skpc
    			goto onbklit		; If yes, activate backlit.
    			goto offbklit		; Else, off backlit.
    
    onbklit		bsf PORTC, 3
    			goto brkdigbrite
    offbklit	bcf PORTC, 3
    			goto brkdigbrite
    			
    brkdigbrite	
    			banksel briteH
    			movf briteH, w
    			movwf rmng_num
    
    			clrf quotient			; Break ADC high byte result to individual digits to be displayed.
    			call get_dig
    			movwf digitbritedata0
    
    			clrf quotient
    			call get_dig
    			movwf digitbritedata1
    
    			clrf quotient
    			call get_dig
    			movwf digitbritedata2
    
    			banksel briteL
    			movf briteL, w
    			movwf rmng_num
    
    			clrf quotient			; Break ADC low byte result to individual digits to be displayed.
    			call get_dig
    			movwf digitbritedataL0
    
    			clrf quotient
    			call get_dig
    			movwf digitbritedataL1
    
    			clrf quotient
    			call get_dig
    			movwf digitbritedataL2
    
    calcbrite					
    				banksel briteL
    				movlw d'13'				; Assign multiplier and clear fractional brightness reading.
    				clrf britefract
    
    mult13			addwf britefract, f		; Multiply ADRESL by 13 to obtain fractional brightness reading.
    				decfsz briteL, f
    				goto mult13
    
    breakbrite		movf briteH, w			; Break up brightness readings to ind. digits to be displayed.
    				movwf rmng_num			
    
    				clrf quotient
    				call get_dig
    				movwf britenonfract0
    
    				clrf quotient
    				call get_dig
    				movwf britenonfract1
    
    				clrf quotient
    				call get_dig
    				movwf britenonfract2
    
    				movf britefract , w
    				movwf rmng_num
    
    				clrf quotient
    				call get_dig
    				movwf britefract0
    
    				clrf quotient
    				call get_dig
    				movwf britefract1
    
    				return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Check status on RC5 to determine whether to pass data to PC.
    ;------------------------------------------------------------------------------------------------------------------------
    
    passdata2pc
    				btfss PORTC, 5
    				goto transdata
    				goto transdone
    
    transdata		movf tempHtrans, w			; Pass temp results to PC.
    				call transmit
    				movf tempLtrans, w
    				call transmit
    				movf briteHtrans, w
    				call transmit
    				movf briteLtrans, w
    				call transmit
    
    				goto transdone
    
    transdone		return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; Check status on RC4 and display the data.
    ;------------------------------------------------------------------------------------------------------------------------
    
    displaydata		movlw d'48'					; Convert individual digits to ASCII.
    				addwf digittempdata2, f
    				addwf digittempdata1, f
    				addwf digittempdata0, f
    				addwf digittempdataL2, f
    				addwf digittempdataL1, f
    				addwf digittempdataL0, f
    
    				addwf tempnonfract2, f
    				addwf tempnonfract1, f
    				addwf tempnonfract0, f
    				addwf tempfract1, f
    				addwf tempfract0, f
    
    				addwf digitbritedata2, f
    				addwf digitbritedata1, f
    				addwf digitbritedata0, f
    				addwf digitbritedataL2, f
    				addwf digitbritedataL1, f
    				addwf digitbritedataL0, f
    
    				addwf britenonfract2, f
    				addwf britenonfract1, f
    				addwf britenonfract0, f
    				addwf britefract1, f
    				addwf britefract0, f
    
    				btfss PORTC, 4			; Check Pin 4 of PORTC. If HIGH then display calc. data.
    				goto debugdata			; Else, display raw ADC data.
    				goto userdata		
    
    debugdata		call cursorhome			; Reposition cursor to home.
    
    				movlw A'A'				; Displays "ADRES0 xxx yyy"
    				call PUTCHAR			;		   "ADRES1 xxx yyy"
    				movlw A'D'
    				call PUTCHAR
    				movlw A'R'
    				call PUTCHAR
    				movlw A'E'
    				call PUTCHAR
    				movlw A'S'
    				call PUTCHAR
    				movlw A'0'
    				call PUTCHAR
    
    				movlw A' '
    				call PUTCHAR
    				movf digittempdata2, w
    				call PUTCHAR
    				movf digittempdata1, w
    				call PUTCHAR
    				movf digittempdata0, w
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movf digittempdataL2, w
    				call PUTCHAR
    				movf digittempdataL1, w
    				call PUTCHAR
    				movf digittempdataL0, w
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    
    				call nextline
    
    				movlw A'A'
    				call PUTCHAR
    				movlw A'D'
    				call PUTCHAR
    				movlw A'R'
    				call PUTCHAR
    				movlw A'E'
    				call PUTCHAR
    				movlw A'S'
    				call PUTCHAR
    				movlw A'1'
    				call PUTCHAR
    
    				movlw A' '
    				call PUTCHAR
    				movf digitbritedata2, w
    				call PUTCHAR
    				movf digitbritedata1, w
    				call PUTCHAR
    				movf digitbritedata0, w
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movf digitbritedataL2, w
    				call PUTCHAR
    				movf digitbritedataL1, w
    				call PUTCHAR
    				movf digitbritedataL0, w
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    
    				goto displaydone
    
    userdata		call cursorhome			; Reposition cursor to home.
    
    				movlw A'T'				; Display message "Temp    xxx.yy C"
    				call PUTCHAR			;                 "Light   xxx.yy %"
    				movlw A'e'
    				call PUTCHAR
    				movlw A'm'
    				call PUTCHAR
    				movlw A'p'
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    
    				movf tempnonfract2, w
    				call PUTCHAR
    				movf tempnonfract1, w
    				call PUTCHAR
    				movf tempnonfract0, w
    				call PUTCHAR
    				movlw A'.'
    				call PUTCHAR
    				movf tempfract1, w
    				call PUTCHAR
    				movf tempfract0, w
    				call PUTCHAR
    				movlw b'11011111'
    				call PUTCHAR
    				movlw A'C'
    				call PUTCHAR
    
    				call nextline
    
    				movlw A'L'
    				call PUTCHAR
    				movlw A'i'
    				call PUTCHAR
    				movlw A'g'
    				call PUTCHAR
    				movlw A'h'
    				call PUTCHAR
    				movlw A't'
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    				movlw A' '
    				call PUTCHAR
    
    				movf britenonfract2, w
    				call PUTCHAR
    				movf britenonfract1, w
    				call PUTCHAR
    				movf britenonfract0, w
    				call PUTCHAR
    				movlw A'.'
    				call PUTCHAR
    				movf britefract1, w
    				call PUTCHAR
    				movf tempfract0, w
    				call PUTCHAR
    
    				movlw A' '
    				call PUTCHAR
    				movlw A'%'
    				call PUTCHAR
    
    displaydone		return
    
    ;------------------------------------------------------------------------------------------------------------------------
    ; End of Programme.
    ;------------------------------------------------------------------------------------------------------------------------
    				end
    [/tag]
    Last edited by danko; 07-03-2007 at 08:43 PM.

  10. #10
    Deathray Engineer MacGyver's Avatar
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    Quote Originally Posted by danko View Post
    Mac, sorry for the trouble anywhere to learn Assembly fast?
    Fast? No, not really. A good knowledge of C will speed up the learning process, but you're still looking at weeks or longer, even if you really, really understand what you're doing. And that's just to gain the knowledge to write simple, beginner programs.

    Quote Originally Posted by danko View Post
    I'm really desperate.
    Who isn't? If you're really desparate, offer to pay someone to write it for you (ie. rentacoder.com or w/e and possibly the recruitment section of these forums.).

    Quote Originally Posted by danko View Post
    My C is also not that good, just alot of basic stuffs that i know.
    Then as I said, I doubt you really want to work with assembly.

    I'm unfamiliar with the hardware, so I'm unable to suggest a means of writing the code for it, but there should, hopefully, be some documentation on it somewhere for you to read up on.

  11. #11
    and the hat of wrongness Salem's Avatar
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    You really don't need to know that much assembler to get the general idea of what is going on. Most assembler code is pretty well commented by necessity.

    But in essence, your problem boils down to
    - read sensor
    - perform conversion
    - display result
    And repeat forever

    So work backwards through the problem, so you always have a pretty good idea of what is going on, say
    1. Display a constant string.
    2. Perform a conversion on a numeric constant, then as step 1.
    3. Read a value from the sensor, then as step 2.

    www.avrfreaks.net is another place where a lot of this embedded stuff gets talked about.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  12. #12
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    Salem, yes that's the general concept of what i want to do. But i lack the skills to do it.

    Can i like find seperate samples of it and combine it together?? so far the only thing i learned in school is dsiplaying the results, that's the most confident part for me. It's the conversion that i'm really stuck at.

    I've got another set of codes over the net. I think it's something like that

    Code:
     #include <p18f452.h> 
    #include <adc.h> 
    #include <stdlib.h> 
    
    
    #define    out1        LATBbits.LATB0 
    #define    out2        LATBbits.LATB1 
    
    void delay(unsigned short i); 
    
    
    void main (void) 
    { 
       TRISB=0b00000000; 
       TRISA=0b11111111; 
    
       while(1) 
       { 
    
       int temp; 
       int i; 
       out1=0; 
       out2=0; 
    
    
           OpenADC(ADC_FOSC_8 & ADC_RIGHT_JUST & ADC_7ANA_1REF,ADC_CH0 & ADC_INT_OFF); 
           ConvertADC(); 
           while(BusyADC()); 
           temp = ReadADC(); 
           CloseADC(); 
    
       if (temp>X) 
       { 
           out1=1; 
           delay (500); 
       
       } 
       else if (temp <Y) 
       { 
           out2=1; 
           delay (500); 
       
       } 
       else 
       { 
           out1=0; 
           out2=0; 
       } 
    
       } 
    } 
    
    void delay(unsigned short i)            //delay subroutine 
    { 
       for( ; i>0; i--);                    //"for" loop 
    }
    The person who wrote this set of code says she don't know what's
    variables X & Y. Do you think i can work on this to make it display
    on the LCD?

  13. #13
    and the hat of wrongness Salem's Avatar
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    If you can find the relevant bits in two separate programs (reading the ADC and writing the LCD), then you should be able to combine them.

    Since you're "on chip", then everything is highly specific to your particular hardware setup, like how everything is wired together, what tools you're using etc.

    It's best to work on small bits of code at a time. The scope for messing things up is pretty high and the means by which you can analyse what went wrong are very limited.

    Like I said before, you've got a nice LCD display which can be your friend when it comes to debugging. So getting that bit right first will make the next steps a lot easier since you have some chance to use the LCD for debug as well as output.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  14. #14
    Registered User
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    Any tips for the conversion anyone??.

    Salem, you always simplify things best for me. Could you tell me in lay man terms the concept of conversion from the AC signals that the sensors receives, to Digital form that the chip can read? Am i asking too much? =X

    What you meant by "nice LCD" ??

  15. #15
    and the hat of wrongness Salem's Avatar
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    > to Digital form that the chip can read?
    That's what the 3 lines ending with
    temp = ReadADC();
    do.

    The rest could be as simple as sprintf()

    > What you meant by "nice LCD" ??
    As opposed to the handful of LEDs and a serial line which the more basic platforms provide.
    It's nice because it's there on the board ready for you to use
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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