I am confuse

[mackrackit]

I picked up the below method of reading the ADC here
http://www.rentron.com/PICX2.htm
I like it much better than ADCIN.

The below code is an example for reading ADC channel 0. Look at the example on the above link to add other channels.

It looks like a lot of stuff to do to read the ADC, pretty much what ADCIN does behind the scenes. This way you have control.
The "READ_AD" part is only needed once no matter how many channels you are reading (reusable).

Use your LCD or SERIAL to see what is happening. I have this running at 2400 baud. Works OK with the internal OSC for testing.

[color=#000000]    '16F88 ADC TEST  FOR CHANNEL 0
    DEFINE OSC 4           
    OSCCON = %01100000
    @ __config _CONFIG1, _INTRC_IO & _WDT_OFF & _LVP_OFF & _MCLR_OFF &_CP_OFF
    ANSEL = %00001111
    TRISA = %11111111
    CHAN0  VAR WORD   'VAR TO HOLD ADC0 READING
    START:
    HIGH PORTB.3    'HEART BEAT
    PAUSE 250
    LOW PORTB.3
    PAUSE 250
    'BELOW WILL SHOW WHAT THE ADRESH AND ADRESL REGISTER HOLDS
    SEROUT2 PORTB.2, 16780, ["ADRESH ",DEC ADRESH," ADRESL ",DEC ADRESL,$a,$d]
    PAUSE 50
    'BELOW SHOWS THE 10 BIT READING OF ADC0 IN VAR CHAN0
    SEROUT2 PORTB.2, 16780, ["CHAN0 ",DEC CHAN0,$a,$d]
    GOSUB ADC_0      'STARTS THE READING OF ADC CHANNEL 0
    GOTO START
    
    ADC_0:       'READ AN0
    ADCON1 = %10000000      'SET FOR 10 BIT
    ADCON0 = %00000001      'TURNS ADC ON
    GOSUB   READ_AD
    CHAN0.HighByte = ADRESH  'PLACES THE HIGH AND LOW BYTE
    CHAN0.LowByte  = ADRESL   'INTO VAR CHAN0
    RETURN
    
    READ_AD:   'DOES THE ADC CONVERSION
    PAUSE   50
    ADCON0.2 = 1
    PAUSE   50
    RETURN  

[Melanie]

You can actually improve on that Dave...

Instead of...

ADCON0.2=1
PAUSE 50
RETURN

... which makes the assumption that your ADC reading will complete in 50mS... well - suppose it didn't? And suppose it only took only 50uS then you've wasted a shed load of time!

So, rather than a hit or miss approach, nail it properly...

ADCON0.2=1
WHILE ADCON0.2=1:WEND
RETURN

To find out why I've done this, read the Datasheet description for pin ADCON0.2

[Acetronics2]

A2D8.bas example program, in the SAMPLES Folder ...

While ... Wend did not exist in those prehistoric times this example was written ...


Still no code available from tim ???

Alain

[mackrackit]

COOL!!!

This is what I have said. You learn by trying to help.
Been using something like I posted all along and of course I have read that part about that bit but it never clicked...

Maybe that is why it is called GO/DONE

Prehistoric??? Maybe there is another message here.

[Melanie]

Well even in prehistoric times IF was available to you...

	ADCON0.2=1
ADCTIMEOUT:
	IF ADCON0.2=1 THEN ADCTIMEOUT
	RETURN

[Acetronics2]

Hi, Mel

my prehistorics datings ( 14 Carbide ...) are V2.21 ...

mainloop: ADCON0.2 = 1		' Start Conversion

notdone: Pause 5
	If ADCON0.2 = 1 Then notdone	' Wait for low on bit-2 of ADCON0, conversion finished

	adval = ADRESH		' Move high byte of result to adval

of course it's impossible you knew it, may be your grand'dad ...

I suspect " Pause 5 " here for 10,000 microns handcarved silicium "1650" processor ( PIC's ancester )...

Regards
Alain

[timseven]

Well after reading all of your posts and did some research on the 16f88 datasheet I applied some changes to my own program that looks it has improved. With all channels 0 to 3 straight to ground I got channels 2 and 3 to 0 and channels 0 and 1 to some value of 14. I am adding the program listing for your evaluation. Thank you in advance.


@ __config _CONFIG1, _INTRC_IO & _WDT_ON & _LVP_OFF & _CP_OFF

INCLUDE "modedefs.bas"
ANSEL = %00001111 'set RA0-RA3 as analog inputs
ADCON1 = %10000000 'Right Justifies 10-bit value
OSCCON = $60 'Sets the internal oscillator to 4 Mhz
CMCON = 7 'Comparators off

DEFINE ADC_BITS 10 ' Sets the number of bits in the result to 10

ti var byte
ti = 50 '20 MILLISECONDS DELAY'
A VAR word
B VAR word
C VAR word
D VAR word
TRISA = %00001111
TRISB = 0 'TURN PORT B as outputs but RB1 WHEN USE ICD FOR COMMUNICATION

'* * * * * MAIN PROGRAM START HERE * * * * * * * *

PAUSE 1000
Serout PORTB.1, 0, [254,1]
Serout PORTB.1, 0, [254,2]
PAUSE 20

READSENSORS:

ADCON0 = %00000001 'Turn ON CHAN 0
GOSUB ADCON
A.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR
SEROUT PORTB.1 , 0, ["Ch 0= ",# A.LOWBYTE]
pause 20

ADCON0 = %00001001 'Turn ON CHAN 1
GOSUB ADCON
B.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR
SEROUT PORTB.1 , 0, [" Ch 1= ",# B.LOWBYTE]
PAUSE 20

SEROUT PORTB.1,0,[$FE,$C0]

ADCON0 = %00010001 'Turn ON CHAN 2
GOSUB ADCON
C.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR
SEROUT PORTB.1 , 0, ["Ch 2= ",# C.LOWBYTE]
PAUSE 20

ADCON0 = %00011001 'Turn ON CHAN 3
GOSUB ADCON
D.LOWBYTE = ADRESL 'PLACES THE LOW BYTE INTO VAR
SEROUT PORTB.1 , 0, [" Ch 3= ",# D.LOWBYTE]
PAUSE 1000

Serout PORTB.1, 0, [254,1]

GOTO READSENSORS ' PROVISIONAL LOOP TO CHECK THE A/D CONVERTION.

'* * * * * * * * * SELECTING THE MOTOR MOVEMENT * * * * * * * *

IF A =0 and D =0 or C =0 and b =0 THEN GOTO READSENSORS 'IT IS DARK
IF ABS (A-D)<10 OR ABS (B-C)<10 THEN GOTO READSENSORS 'IT IS ALIGNED

If (B>D) OR (A>C) Then gosub Front
IF (A>B) OR (C>D) THEN GOsub Left
IF (C>A) OR (D>B) THEN GOsub Back
IF (D>C) OR (B>A) THEN GOsub Right

GOTO READSENSORS 'STAY FOR EVER LOOPING

'* * * * * * * * * MOTOR'S MOVEMENTS SUBRUTINES * * * * * * * *

Front:
Serout PORTA.6, 0, ["FRONT ",# ABS (B-D)," ",# ABS (A-C)]
SEROUT PORTA.6, 0, [$FE,$C0]
PORTB = 1 'GOING FRONT
PAUSE TI
PORTB = 2
PAUSE TI
PORTB = 4
PAUSE TI
PORTB = 8
PAUSE TI
Return
LEFT:
Serout PORTA.6, 0, ["LEFT ",# ABS (a-b)," ",# ABS (C-D)]
SEROUT PORTA.6, 0, [$FE,$C0]
PORTB = 128 'GOING LEFT
PAUSE TI
PORTB = 64
PAUSE TI
PORTB = 32
PAUSE TI
PORTB = 16
PAUSE TI
Return

Back:
Serout PORTA.6, 0, ["BACK ",# ABS(C-A)," ",# ABS(D-B)]
SEROUT PORTA.6, 0, [$FE,$C0]
PORTB = 8 'GOING BACK
PAUSE TI
PORTB = 4
PAUSE TI
PORTB = 2
PAUSE TI
PORTB = 1
PAUSE TI
Return
RIGHT:
Serout PORTA.6, 0, ["RIGHT ",# ABS(D-C)," ",# ABS(B-A)]
SEROUT PORTA.6, 0, [$FE,$C0]
PORTB = 16 'GOING RIGHT
PAUSE TI
PORTB = 32
PAUSE TI
PORTB = 64
PAUSE TI
PORTB = 128
PAUSE TI
Return

ADCON:
ADCON1 = %10000000 'SET FOR 10 BITS
ADCON0.2 = 1 'IT'S ONE TILL IT READS
WHILE ADCON0.2 = 1 : WEND
RETURN

END