ds18s20 reads incorectly

[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.

[Acetronics2]

Why not use PBP's built-in OWIN/OWOUT commands?

The solution simply is here ...

MKB reads Byte by Byte and Pbp ... as you want !

just need to program a correct reading with Pbp !



Further ... TempF = TempC *9/5 + 32 ...

Remember PbP works with UNSIGNED INTEGERS ...

Alain

PS: Ski, MKB has a built-in timing adjustment,( you check an option in the project window instead of writing a DEFINE ) and The "conversion complete" polling built-in. That surprised me a bit at first time, not to see it in the source listing ...

[jcleaver]

the osc is correct dont know why it did not show caps
tried going with 4 still read low
? what changes in math
TEMP = ((TEMP*9/5)+32 ) is what i am using
thanks for the inputs

have not found any samples using owin with this chip

[Acetronics2]

Hi,

Did you ever try SEARCH with the 1820 Keyword ???

Surely NO !!!

I remember having posted a while ago for the DS1820 ...

Gives ... 22 Hits !

Alain

[skimask]

I remember having posted a while ago for the DS1820 ...
Gives ... 22 Hits !
Alain

23 Hits now!
But, he's also using the DS18S20.
I know...I know...not a lot of difference between the two that can't be handled by a simple read of the datasheet.

[skimask]

the osc is correct dont know why it did not show caps
tried going with 4 still read low
? what changes in math
TEMP = ((TEMP*9/5)+32 ) is what i am using
thanks for the inputs

have not found any samples using owin with this chip

Ok, try this:

@ DEVICE pic16F877A, HS_OSC
@ DEVICE pic16F877A, WDT_ON
@ DEVICE pic16F877A, PWRT_ON
@ DEVICE pic16F877A, BOD_ON
@ DEVICE pic16F877A, MCLR_on
@ DEVICE pic16F877A, LVP_OFF
@ DEVICE pic16F877A, CPD_OFF
@ DEVICE pic16F877A, PROTECT_OFF
define osc 20
define loader_used 1
define lcd_dreg portd
define lcd_dbit 4
define lcd_rsreg portd
define lcd_rsbit 2
define lcd_ereg portd
define lcd_ebit 3
define lcd_lines 2
define lcd_bits 4
define lcd_commandus 2000
define lcd_dataus 50
command var byte:i var byte:temp var word:dq var porta.5:dq_dir var trisa.5
adcon1=255:porta=255:portb=0:trisa=255:trisb=0:cmcon=7
Lcdout $fe,1,"Temp in degrees C"
mainloop:	Gosub init1820:command=$cc:Gosub write1820:command=$44
Gosub write1820:Pause 2000:Gosub init1820:command=$cc:Gosub write1820
Pause 2000:command=$be:Gosub write1820:Gosub read1820:TEMP=((TEMP*9/5)+32)
Lcdout $fe,1,dec(temp>>1),".",dec(temp.0*5)," degrees C":Goto mainloop
init1820:	Low DQ:Pauseus 500:DQ_DIR=1:Pauseus 100
If DQ=1 Then Lcdout $fe,1,"DS1820 not present":Pause 500:Goto mainloop
Pauseus 400:Return
write1820:	For i=0 to 7:low dq
If command.0[temp] = 0 Then
	Pauseus 60:DQ_DIR = 1
Else
	@ nop
	DQ_DIR = 1:Pauseus 60
Endif
Next i:Return
read1820:	For i=0 to 15:low dq
		@ nop
		dq_dir=1:temp.0[i]=1:if dq=0 then temp.0[i]=0
		pauseus60:next i:return
End

[jcleaver]

Tried This And Get Better Reading Only 6 Deg Low

However It Does Not Respond To Any Temperature Changes

Thanks

[skimask]

Tried This And Get Better Reading Only 6 Deg Low
However It Does Not Respond To Any Temperature Changes
Thanks

Ok, what DOES it put out for a temperature?

What happens if you heat it up, read the temperature, shut it off, put it in the freezer for a few minutes, take it out, power it up and read the temp right away?

[jcleaver]

Read 65.xxxx

Does Not Update Hold Sensor And Nothing Changes

Reloaded Several Programs And They Work However Still Get Low Tmp Reading

Dont Think Its A Hardware Problem Because It Works Perfectly In Mikroe

Guess I Could That But Have Better Luck With Pbp As For As Adding My Stuff