16F1827 ADC Direct manipulation not working

[Ioannis]

While using ADCin works fine, using direct register manipulation does not. Can anyone tell me why?

PORTA = 0
PORTB = 0
TRISA = %00000011
TRISB = %00001011

ADCON0 = %00000000      'select channel AN0, ADC off
ADCON1 = %01110000      'Internal Frc, Left justified, Ext. ref.

ANSELA = %00000001           ' AN0 on Port A analog
ANSELB = %00000000           ' Digital inputs

start:
adcon0.1=1
while adcon0.1:wend
hserout ["Adresh: ",#adresh,13,10]
pause 1000
goto start

The above does not work. The next one works just fine though...

start:
pause 1000
adcin 0,i
hserout ["Adc: ",#i,13,10]
goto start

Thanks,
Ioannis

[mark_s]

Hi Ioannis,

I think your while loop needs to be

ADCON0.1=1
WHILE ADCON0.1=1
wend

[Darrel Taylor]

while adcon0.1 and while adcon0.1=1 are functionally identical.

However, the A/D module must be turned on before it will perform a conversion.

ADCON0.0 = 1

PBP does that automatically.

[Ioannis]

Hi Darrel.

Thanks for looking at this. Well, I do have this line, just did not copy it when posting the thread.

The strange thing is that, if I use both ways, ADCin and register manipulation, it works!

Like this works fine:

high adcon0.0'=1

start:
adcon0.1=1
while adcon0.1:wend
hserout ["Adresh: ",#adresh,13,10]
pause 1000

adcin 0,i
hserout ["i: ",#i,13,10]
goto start

But not when modified to this:

high adcon0.0'=1

start:
adcon0.1=1
while adcon0.1:wend
hserout ["Adresh: ",#adresh,13,10]
pause 1000

'adcin 0,i
'hserout ["i: ",#i,13,10]
goto start

Cannot figure out why...
Ioannis

[Ioannis]

OK, I found something but cannot tell if it is a bug or something I don't understand.

Setting up the ADCON0 as

ADCON0.0=1
PAUSEUS 100
ADCON0.1=1

does not work.

But ADCON0=3 does work just fine!

Ioannis

[Ioannis]

Ooops,no bug!

I got it.

Wrong label...

Sorry for the alarm.

All are OK.

Ioannis