Problem with ADC

**savnik** · - 22nd November 2006, 11:13

I have this configuration in my program

Code:

' ******************************** LCD **************************************

    DEFINE LCD_DREG PORTB		    'Selection of the port B
    DEFINE LCD_DBIT 4
    DEFINE LCD_RSREG PORTB		    'RS on port RA1
    DEFINE LCD_RSBIT 2
    DEFINE LCD_EREG PORTB		    'E on port RA0
    DEFINE LCD_EBIT 3
    DEFINE LCD_BITS 4		        'Mode 4 bits
    DEFINE LCD_LINES 4		        'LCD 4 lines of 16 caracter
    
	PAUSE 500

' Define ADCIN parameters
    
    DEFINE  ADC_BITS        8     	'Set number of bits in result
    DEFINE  ADC_CLOCK       3     	'Set clock source (3=rc)
    DEFINE  ADC_SAMPLEUS    50    	'Set sampling time in uS
	
    INCLUDE "LCDbar_INC.bas"        'Include the BARgraph routines
		
    CMCON = 7                       'PortA = digital I/O    
	ANSEL = %00000111               'Will set RA2 as analog and all others as digital

and this asm: (is for frequency meter)

Code:

Asm
	movlw   0x10	       ;PORTA 4 in entry
	movwf   0x5
	MOVLW	0x37
        option      	   ;charge 00110111 in the register option
	MOVLW	0x10		   ;init freq with RA4 in entry
	MOVWF	_trisabuf
EndAsm

and this asm: (is for frequency meter)

Code:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;    AUTHORIZATION OF COUNTING

	       clrf    TMR0		        ; RAZ timer
	       bsf	    _trisabuf,3	    ; RA4 in entry and RA3 in entry authorization counting
	       movf 	_trisabuf,W
	       tris	   PORTA
	
;;;;;;;;;;;;;;;;;;;;;;;;;;;;    BASE TIME  
      
	       movf	   _TEMPS,W
           movwf   _COUNT1
dxxx	   nop
	       decfsz  _COUNT1
	       GoTo	dxxx
	       nop
	       nop
	       Call delay
	       Call delay
	       Call delay
	       Call delay
	       Call delay
	
;;;;;;;;;;;;;;;;;;;;;;;;;;;      STOP OF COUNTING

	       bcf     _trisabuf,3	 ;RA4 in entry and RA3 at Exit to block counting
	       movf    _trisabuf,W         
	       tris    PORTA

My problem is the pot not adjust the volt. Show on lcd only if it is full. If i turn litle the pot the volt go to 0volt on lcd.
If i remove the two code : tris PORTA on asm code at the end of code the pot adjust linear, but the frequency meter
is not show properly.
In the image the resistor is 47omh and the pot 47kohm

**paul borgmeier** · - 22nd November 2006, 14:12

Part of your problem ....

you need TRISA.1 = 1 (RA1 = input) somewhere before doing your ADC.

Your ASM routines clear this bit, making it an output. Do you set it elsewhere before sampling?

Also, why the ASM? Everything you show is easy in PBP?

(side note - OPTION and TRIS are going away .. avoid them – see datasheet)

**savnik** · - 22nd November 2006, 15:02

Thank you very much.
I put TRISA.0 = 1 before ADC and it's work.

**savnik** · - 22nd November 2006, 20:13

Originally Posted by paul borgmeier

Also, why the ASM? Everything you show is easy in PBP?

How change the code from asm to PBP

**paul borgmeier** · - 22nd November 2006, 21:20

For the first block of ASM, replace with

PORTA = $10
TRISABUF=$10
OPTION_REG=$37

You need to post the rest of your ASM code in order for us to see how to completely convert the second block (.i.e, where is your delay routine?)

**savnik** · - 22nd November 2006, 21:30

Originally Posted by paul borgmeier

For the first block of ASM, replace with

PORTA = $10
TRISABUF=$10
OPTION_REG=$37

You need to post the rest of your ASM code in order for us to see how to completely convert the second block (.i.e, where is your delay routine?)

Code:

    FHI		    VAR BYTE
    FLO		    VAR BYTE
    COUNT1		VAR BYTE
    TRISABUF	VAR BYTE
    TEMPS		VAR BYTE

All the ASM code

Code:

Asm
;;;;;;;;;;;;;;;;;;;;;;;;;;;;    AUTHORIZATION OF COUNTING

	clrf	TMR0		        ; RAZ timer
	bsf	_trisabuf,3		        ; RA4 in entry and RA3 in entry authorization counting
	movf 	_trisabuf,W
	tris	PORTA
	
;;;;;;;;;;;;;;;;;;;;;;;;;;;;    BASE TIME  
      
	movf	_TEMPS,W
        movwf	_COUNT1
dxxx	nop
	decfsz	_COUNT1
	GoTo	dxxx
	nop
	nop
	Call delay
	Call delay
	Call delay
	Call delay
	Call delay
	
;;;;;;;;;;;;;;;;;;;;;;;;;;;      STOP OF COUNTING

	bcf	_trisabuf,3		        ;RA4 in entry and RA3 at Exit to block counting
	movf 	_trisabuf,W         
	tris	PORTA
	
;;;;;;;;;;;;;;;;;;;;;;;;;;;      RECUPERATION OF THE METERS
  
calcul	MOVF    TMR0,W		    ;timer   -> work
	MOVWF   _FHI	       	    ;work -> FHI	8 bits of weight strong counting
	clrf	_COUNT1		        ;handing-over has zero meter
Toggle	incf	_COUNT1,F	    ;incrementation of the meter
	bsf	PORTA,3		            ;RA3 a 1
	bcf	PORTA,3		            ;RA3 a 0
	movf	TMR0,W		        ;reading of the timer
	subwf	_FHI,w		        ;it is looked at if the divider incremente the timer
	btfsc	STATUS,2		    ;comparison
	GoTo	Toggle		        ;if the timer did not incremente one starts again
	comf	_COUNT1,F	        ;complement with the meter
	incf	_COUNT1,W	        ;incrementation of the meter
	movwf	_FLO		        ;work -> FLO 	8 bits of weight weak counting
	GoTo fin
	
;;;;;;;;;;;;;;;;;;;;;;;;;;;     BASE TIME 
  
delay   	movlw	197         ;1ms according to AN592
	movwf	_COUNT1          	
	nop                     		
	GoTo	$+1              		
	GoTo	$+1             		
dly	GoTo	$+1              		
	decfsz	_COUNT1         	
	GoTo	dly             		
	Return		            	
fin
EndAsm

**mister_e** · - 22nd November 2006, 22:51

Save us to guess what you want to do... AND give us your PIC model.

There's only few hundreds of model.. but who want to guess?

**savnik** · - 23rd November 2006, 06:19

Originally Posted by mister_e

Save us to guess what you want to do... AND give us your PIC model.

There's only few hundreds of model.. but who want to guess?

My problem solved by paul borgmeier.
My pic is 16f88.

**paul borgmeier** · - 23rd November 2006, 07:21

His schematic shows a F88 but he fixed his code by adding TRISA.0 = 1 (pot on RA1 not RA0) - does not make sense??

Try this for the second block of ASM code

Code:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;    AUTHORIZATION OF COUNTING
TMR0 = 0
TRISABUF.3 = 1
PORTA = TRISABUF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;    BASE TIME  
COUNT1=TEMPS
PAUSEUS (COUNT*4+2)
PAUSE 5
;;;;;;;;;;;;;;;;;;;;;;;;;;;      STOP OF COUNTING
TRISABUF.3=0
PORTA=TRISABUF
;;;;;;;;;;;;;;;;;;;;;;;;;;;      RECUPERATION OF THE METERS
FHI=TMR0
COUNT1=0
Toggle:
COUNT1=COUNT1+1
PORTA.3=1
PORTA.3=0
IF (FHI-TMR0) = 0 THEN Toggle
COUNT1=(COUNT1^$FF)
FLO=COUNT1+1	
;;;;;;;;;;;;;;;;;;;;;;;;;;;     BASE TIME

Any second opinions on the conversion?

Savnik, what does your program do?

**savnik** · - 23rd November 2006, 09:01

Originally Posted by paul borgmeier

His schematic shows a F88 but he fixed his code by adding TRISA.0 = 1 (pot on RA1 not RA0) - does not make sense??

Try this for the second block of ASM code

Code:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;    AUTHORIZATION OF COUNTING
TMR0 = 0
TRISABUF.3 = 1
PORTA = TRISABUF
;;;;;;;;;;;;;;;;;;;;;;;;;;;;    BASE TIME  
COUNT1=TEMPS
PAUSEUS (COUNT*4+2)
PAUSE 5
;;;;;;;;;;;;;;;;;;;;;;;;;;;      STOP OF COUNTING
TRISABUF.3=0
PORTA=TRISABUF
;;;;;;;;;;;;;;;;;;;;;;;;;;;      RECUPERATION OF THE METERS
FHI=TMR0
COUNT1=0
Toggle:
COUNT1=COUNT1+1
PORTA.3=1
PORTA.3=0
IF (FHI-TMR0) = 0 THEN Toggle
COUNT1=(COUNT1^$FF)
FLO=COUNT1+1	
;;;;;;;;;;;;;;;;;;;;;;;;;;;     BASE TIME

Any second opinions on the conversion?

Savnik, what does your program do?

Sorry ,the pot is on RA0 (the schematic is wrong)

With the first block of asm the frequency meter work.

When i change the second asm with yours code i take error when compile.
When I change the PAUSEUS (COUNT*4+2) with PAUSEUS (COUNT1*4+2) and the Toggle with Toggle1 the code compile , but the frequency on LCD is above 14Mhz the regular (90.6Mhz -> 104.6Mhz)

**paul borgmeier** · - 23rd November 2006, 14:58

Now that it is not 2Am, I see that it might be the PAUSEUS line - PAUSEUS has a minimum delay of 24uS when used with a 4 MHz XTAL. I also took "your" comments about the delay loop as being accurate at 1 mS. I will check that as well.

What XTAL speed are you running?

Unfortuantely, it is "Off to Grandma's House" here as it is a major holiday. I will not have a minute to debug until tomorrow night (36 hours from now). As asked before,

Anyone else have an opinion on the ASM to BASIC conversion or want to take a stab at the problem? If not, I will revisit when I return.

**savnik** · - 23rd November 2006, 15:00

Originally Posted by paul borgmeier

What XTAL speed are you running?

I use 4MHZ xtal.

**paul borgmeier** · - 25th November 2006, 06:38

Also, why the ASM? Everything you show is easy in PBP?

I guess I lied - I do not see an easy solution to the minimum PAUSEUS problem noted above - I am glad it works for you with the ASM blocks.
Good Luck,

**savnik** · - 25th November 2006, 07:37

Originally Posted by savnik

Thank you very much.
I put TRISA.0 = 1 before ADC and it's work.

Thank you again because you solve my problem with ADC.
For the ASM never mind.

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