ds18s20 reads incorectly

[jcleaver]

Finally Got It Working Better
Thanks For The Inputs
Notice I Said Better Still Reads 10 F Deg Low
But Better Really Dont Understand Why Mikroe Works Perfectly With The Same
Hardware Using Pbp 5.0 And Mcsp 3.0
Must Be Some Difference In The Complier No? Maybe?

[manwolf]

I posted a program that reads DS18S20s. I have 4 of them on onewire and I read them with no problem and I use PBP.
I do not expect temps below zero so I have not made allowances for that.

http://www.picbasic.co.uk/forum/showthread.php?t=9116

[Nicmus]

Hi jcleaver,

You might want to check Maxim forum at:

http://discuss.dalsemi.com/index.php?

They had rejects on DS1820 family showing wrong temperature and there is a fix for it.

Nick

[jcleaver]

I Do Appreicate Your Inputs
Manwolf Your Program Looks Great But Way Beyond My Knowledge
And As For As The Ds18 Goes I Have Tried Several

Again To Ask ?
Why Does Mikro Work Where Pbp Does Not
There Has To Be Some Difference In The Compliers

Using Exactly The Same Hardware Easypic4
Could It Be The Math Conversion Using Pbp

Both Programs Use The Same Formula For C To F

[manwolf]

How are you reading the temp form the DS18S20 in PBP?
Are you using one-wire or something else?

[jcleaver]

i have attached the 2 programs one in pbp which reads temperature incorectly
the other mikroe which works no hardware changes are made really interested in the difference


thanks

jack

[skimask]

i have attached the 2 programs one in pbp which reads temperature incorectly
the other mikroe which works no hardware changes are made really interested in the difference


thanks

jack

Speaking strictly about PBP....
You know, just like it says in the manual, define's have to be in CAPS.
Therefore, the
define osc 20
is ignored and the timing generated by the code is generated for an oscillator of 4mhz, but apparently you are running it at 20mhz, and therefore, probably far too fast.
Did you write this code or copy/paste it? Why not use PBP's built-in OWIN/OWOUT commands?

[manwolf]

maybe you should check the math.
With a change to the math the program works correctly. Running on a EasyPIC5 board.

Sorry I was sleeping that day in class, so I can't explain why PBP and MBasic work differently.