Problem with ADC

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- 22nd November 2006, 11:13
savnik

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Problem with ADC

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
- 22nd November 2006, 14:12
paul borgmeier

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)
- 22nd November 2006, 15:02
savnik

problem solved

Thank you very much.
I put TRISA.0 = 1 before ADC and it's work.
- 22nd November 2006, 20:13
savnik

Quote:

Originally Posted by paul borgmeier

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

How change the code from asm to PBP
- 22nd November 2006, 21:20
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?)
- 22nd November 2006, 21:30
savnik

Quote:

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
- 22nd November 2006, 22:51
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?
- 23rd November 2006, 06:19
savnik

Quote:

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.
- 23rd November 2006, 07:21
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?
- 23rd November 2006, 09:01
savnik

Quote:

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)
- 23rd November 2006, 14:58
paul borgmeier

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.
- 23rd November 2006, 15:00
savnik

Quote:

Originally Posted by paul borgmeier

What XTAL speed are you running?

I use 4MHZ xtal.
- 25th November 2006, 06:38
paul borgmeier

Quote:

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,
- 25th November 2006, 07:37
savnik

Quote:

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.