12F508 and Dallas 1820 not working

[Acetronics2]

Are you really sure of your OWIN parameters ???

I'm not !!!

Alain

[fratello]

Sorry... TRISGPIO = %00000010

[Picprogman]

Are you really sure of your OWIN parameters ???

I'm not !!!

Alain

Thank you. I am fairly new with Picbasic, but all that code is directly copied from rentron.com Picbasic sample page. Only changed the DS1820 ID. I again double checked the ID and the code. I have a check board with a suitable program and an LCD. I just plug in any DS18x20 and can I see immediately the ID and CRC-code. By the way, my english may not be good. I am from Finland.


See the original code at Rentron:

http://www.rentron.com/PicBasic/one-wire2.htm

and find Temp_1 label.

The code works exteremely well with my other programs with 16F87xx Pics. I also changed my sample code a bit and used GPIO.2 as data pin. Datasheet says "General Purpose IO-pin", just like PortC-pins on 16F87xx. But this tiny chip is against me. I have also tested another 12F508 without success. Maybe I have to give up

[Picprogman]

Oh sh*t!!!

I had forgotten to connect a pull-up resistor to data pin, and that was the reason for non workin code. I am sorry, that I have caused trouble. The following works. Data pin is now back to GP1 (GPIO.1)

'****************************************************************
'*  Name    : 12F508thermostat.BAS                                          *
'*  Author  : AN OLD FINNISHMAN                    *
'*  Notice  :                                    *
'*            :                                 *
'*  Date    : 02/12/2012                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                    *
'*          :                                                   *
'****************************************************************

' CHIP: PIC 12F508
' A simple program to read DS1820 (18S20) and depending on the temperature
' to drive a led (and/or a solit state relay to drive an 
' electric heater).
' ID for the sensor and a CRC value is here:
' $10,$B2,$AD,$D8,$00,$08,$00,$26
' replace it with yours
' USE INTERNAL OSCILLATOR (INTRC) 

' connect a led via 470 ohm resistor to GP0
' connect a 4k7 pull-up resistor to data pin GP1


Define osc 4

led var GPIO.0


Tempa Var Word            ' Temperature storage
Stat var bit

DQ    Var    GPIO.1            ' One-wire data pin

TRISIO =000010
GPIO =000000

'led on for a second to see if code runnig

        High led 
        PAUSE 1000
        low led

pauseus 100

Temp_1:
    
    OWOUT DQ, 1, [$55,$10,$B2,$AD,$D8,$00,$08,$00,$26,$44]
W1:
    OWIN DQ, 4, [Stat]' Check for still busy converting
    IF Stat = 0 THEN W1' Still busy?, then loop
    OWOUT DQ, 1,[$55,$10,$B2,$AD,$D8,$00,$08,$00,$26,$BE]
    OWIN DQ, 2, [Tempa.LOWbyte,Tempa.HIGHBYTE]' Read two bytes, then end communications
    
' replace upper and lower limits with your own
' variable Tempa is 2 times the temperature in degrees C
    
If Tempa >= 41 then low led ' if temp >= 20,5 (upper limit)
If Tempa <= 40 then High led ' if temp <= 20 (lower limit)

PAUSE 1000

Goto Temp_1