Problem with ADC

[savnik]

I have this configuration in my program



' ******************************** 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)



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)



;;;;;;;;;;;;;;;;;;;;;;;;;;;; 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]

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]

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

[savnik]

Also, why the ASM? Everything you show is easy in PBP?
How change the code from asm to PBP

[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?)

[savnik]

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?)


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


All the ASM 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]

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]

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]

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



;;;;;;;;;;;;;;;;;;;;;;;;;;;; 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]

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



;;;;;;;;;;;;;;;;;;;;;;;;;;;; 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]

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]

What XTAL speed are you running?

I use 4MHZ xtal.

[paul borgmeier]

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]

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.