16f877 with LM335 problem

[CrazyCooter]

Did you really bought the copy of PBP you have????

Did it came with it a MANUAL ???

Did you read the MANUAL ????

Didn't find any reference as to that PBP is NOT supporting floating maths ???

I am looking forward to you replying to the above so that we can continue support here.

Ioannis


P.S. If you are just connect the sensor to the PIC directly, your useful range will be limited (0C-100C is from 2,7315 to 3,7315 Volts). I suggest to use opamps and extend the range of the sensor from 0C->0Volts to 100C->5 Volts.

thanks for the quick responce

got PBP 2.47 from DONTRONICS here in melbourne

Yes. Read the 213 pages and even been looking up web sites with references. downloaded the data sheet read the A2D converter module.. CH 11 pg 127

ok just found 1 error in setting the TRISA had 8 bits set to 1 should have been 6 ie TRISA %111111 not TRISA %11111111

still not workin. even connected a 5k lin pot and got no responce.


and as Ioannis said using an opamp to extend the range i will be now

MY CODE WILL NOT COMPILE WITH THIS LINE
AD_RESULT = (ad_raw *0.48828) - 273.15

Had to do it this way
ad_result = (ad_raw * 48828)/1000
ad_result = ad_result/100
ad_result = (ad_result *27315)/100
WHY????????????????????????????????????????
HMMMMMMM very frustrating

[skimask]

MY CODE WILL NOT COMPILE WITH THIS LINE
AD_RESULT = (ad_raw *0.48828) - 273.15

Had to do it this way
ad_result = (ad_raw * 48828)/1000
ad_result = ad_result/100
ad_result = (ad_result *27315)/100
WHY????????????????????????????????????????
HMMMMMMM very frustrating

What do you mean why? Did you read the post earlier? Did you really read it? Let me quote one line from that earlier post:

"Did you read the MANUAL ????

Didn't find any reference as to that PBP is NOT supporting floating maths ???"

How many times do we have to point out to you that PBP does not support floating point math! And if you don't understand the term 'floating point', well, quite frankly 'floating point' means that the decimal is 'floating'...it can move wherever it needs to go according to the math being performed!
PBP DOES NOT SUPPORT FLOATING POINT MATHS! The decimal point is stuck in one place, all the way to the right, no matter what you do, the decimal point will always be to the right...no fractions, no tenths, no hundreths, no nothing. If you divide 10 by 3, you'll get 3, nothing more nothing less. If you use the remainder function, yes, in the case above, you'll get a 1 from it, but it's still not FLOATING POINT...

Somebody get me a drill!!!

[CrazyCooter]

Thanks skimask for pointing that out.

ok so i am 1 step closer to getting this to work now.

so the only way to do floating point maths then is with asm right?

and thats why my code will not work correctly with the LM335 and the ADC?

[Acetronics2]

QUOTE << Hi, Skimask

You can also remember Every number can be close-rounded as the division of two integers ... ( PI = 22/7 i.e. )

That give some brain work to find the couple of the year ... but a small GWBASIC ( LOL !!! ) program can easily sort them.

With the use of the DIV32 function ... that enables more than you ever dreamed !!!

Alain >>

Hi, Scooter

Sometimes, life is really funny ... that comes from 5 threads down on the list ...

[skimask]

Thanks skimask for pointing that out.

ok so i am 1 step closer to getting this to work now.

so the only way to do floating point maths then is with asm right?

and thats why my code will not work correctly with the LM335 and the ADC?

Sure, because a byte/word/bit/whatever has a decimal point in it when written in plain text...

It's possible to do plenty of floating point when using straight PBP, as many digits as you want, as much accuracy as your heart desires......the question is, can you?

[CrazyCooter]

It's possible to do plenty of floating point when using straight PBP, as many digits as you want, as much accuracy as your heart desires......the question is, can you?

I have no understanding of asm so would take me a very long time to understand and implement.

2 decimal places is more than accurate enought for what i want to be doing
and all the adc will be from 0V to 5V in 10 bit

as Ioannis said "check the manual and forum for applications of DIV32, */ and // operators. These are what you need to do the job."

thanks everyone see how i go trying this