ds18s20 reads incorectly

[jcleaver]

Manwolf
Worked With Your Pbp And Your Right It Is Displaying The Correct C Temperature

Its Pb Math Thats Incorect

Any Ideas How ?

Also The Formula Temp = ((temp*1.8)+32) Gives Corect Answer But Wont Compile
On Pbp

[manwolf]

Jack

As Acetronics stated:

Remember PBP works with UNSIGNED INTEGERS ...

So 9/5 = 1.8 still won't fly in PBP

How about something like this?

temp = (((temp >> 1) * 100) - 25) 'calculate degrees C

temp = (temp */ 461) + 3200 'convert degrees C to F

And before you ask, crack open the ugly green book and figure out what '*/' does.

Hint: it uses all unsigned integers.

The hardest part of writing any program is learning how to handle the math. If you can not get your head around the math none of this stuff makes any sense.

Don't be afraid to throw some output in there to see what is happening. Run Debug, output to LCD or a serial port to see what it is changing.


For a better explaination of the math go here - http://www.rentron.com/PicBasic/one-wire3.htm

Ted

[Acetronics2]

Hi, Manwolf

What do you mean by that :

" Acetronics: May I play around with the thermostat program you posted? "

Of course YOU can play with it ...

Alain

[Bruce]

Your bit-banged read & write routines use a @ NOP for a 1uS delay, but you're running
at 20MHz so these are only 200nS. You would need 5 x @ NOP for a 1uS delay.

[jcleaver]

Thanks For The Math Help
As For As Speed Goes I Have Treid 4 And 20 Does Not Make A Difference

Will Work On The Math Issue

Do You Have The Thermostat Program In Pbp Not Hex

Thanks

[Acetronics2]

Hi, Jcleaver

The thermostat program was for you to verify what you had to find ... and show you a different Bargraph view.

NOT to copy / paste it ...

You can find any parts of it on this forum, The DS18x20 subject has been widely explored during the past months.

but that need some little efforts ... is it the problem ?

Alain

[skimask]

NOT to copy / paste it ...
...............................
but that need some little efforts ... is it the problem ?

Awwwww!!!!!