10 bits ADCIN with 18F2520

[hwhisperer]

Hello, I hope my question is not something stupid...
I tryed to check in the old posts but I found not one answer....

I was using ADCIN (8 Bits) with this code:

TRISA=255
ADCON1=0
DEFINE OSC 40
DEFINE ADC_BITS 8
DEFINE ADC_SAMPLEUS 50

and:

ADCIN 0, STORE_0

where STORE_0 is a byte sized variable, and it works perfet.

Now I tryed to perform a 10 bit conversion, I used a word sized variable and the define was modified in:

DEFINE ADC_BITS 10

...but it store again one value large one byte, no more...

Can someone help me posting a piece of working code for 18F2520?
Thanks
Stefano

[Kamikaze47]

I'm not sure if this is the problem, but try:

ADCON2.7=1

[timmers]

I never had any luck with DEFINE ADC_BITS 8 it allways wanted to work in 10 bit. But if you only need 8 bit, do an ADCIN with DEFINE_BITS 10 to a word variable then divide the answere by 4.

[hwhisperer]

I'm not sure if this is the problem, but try:

ADCON2.7=1

I tryed... should be someting else becouse it dont works...
thanks
Stefano

[hwhisperer]

I never had any luck with DEFINE ADC_BITS 8 it allways wanted to work in 10 bit. But if you only need 8 bit, do an ADCIN with DEFINE_BITS 10 to a word variable then divide the answere by 4.

Thanks but my problem is the opposite... it works with DEFINE ADC_BITS 8 and give me a byte value... but I need more precision and DEFINE_BITS 10 dont works in my code! :-(
Bye
Stefano

[mackrackit]

where STORE_0 is a byte sized variable, and it works perfet.

Now I tryed to perform a 10 bit conversion, I used a word sized variable and the define was modified in:

DEFINE ADC_BITS 10

...but it store again one value large one byte, no more...


Try a WORD size variable.

[hwhisperer]

Try a WORD size variable.

I did it.

The value is stored in one word size variable but the value never come bigger than 255 (the same value I had when I used the 8 bits define).

stefano

[mackrackit]

This is for a different chip but it might help. I like dealing with the registers directly, an example of both are here.
http://www.picbasic.co.uk/forum/showthread.php?t=11947&p=79694#post79694

[Darrel Taylor]

This works for 10-bit A/D on an 18F2520, using 9600 baud serial to a PC to view the results.

DEFINE OSC 40

SerPin VAR PORTC.6

DEFINE ADC_BITS 10 ; 10-bit results
ADCON2.7 = 1 ; right justify

ADval VAR WORD

Main:
ADCIN 0, ADval
SEROUT2 SerPin, 84,[DEC ADval,13,10]
PAUSE 500
GOTO Main

[hwhisperer]

Thanks to all...
I will try the code and I will reply!
Stefano