Post by thread:newbie, pic basic

I *just* started messing with electronics so I know very little. I am trying to interface a PIC 16F84 with an LM75 temp sensor and send results to a serial LCD. I am useing PIC BASIC can anyone help me with my code/hardware? I don't think I have it right? thanks a bunch.. I realy want to get this working! Regards, Ryan Symbol con = %10010000 '(pins 5,6,an7 on the LM75 tied to ground) Symbol addr = B5 ' Loop: addr = 17 ' Set address to 17 I2Cin con,addr,B2 ' Read data at address 17 into B2 (equation here?...is data read from LM75 in correct format?) 'send to serial LCD Symbol SO = 0 ' Serial Out (this is pin A0 I think) Serout SO, N9600, (B2) ' Send Character at 9600 to serial LCD Pause 50 Goto Loop ' go again

Hi Ryan and Folks, > I am trying to interface a PIC 16F84 with an LM75 temp sensor and send > can anyone help me with my code/hardware? I don't think I have it right? > Symbol con = %10010000 '(pins 5,6,an7 on the LM75 tied to ground) The good controll byte is the 01001000 > Symbol addr = B5 ' ??? > addr = 17 ' Set address to 17 Ryan, there is only 4 registers in the LM47 00000000=temperature reg. 00000001=conmfiguration reg. 00000010=T_hyst 00000011=T_os So, if you would like to read the temperature your address is 0 . > I2Cin con,addr,B2 ' Read data at address 17 into B2 You can read 8 bites of the temperature register with the following program. symbol con=%01001000 symbol addr=b2 symbol temp=b0 addr=%00000000 I2cin con,addr,temp . . . . Unfortunatelly the Pbasic compiler can't read the 16 bit from the LM75 so we loose the two lsb bits( I think). If we want to get the another 8 bits we have to ask the listers to help us (please). Chers George

> > Symbol con = %10010000 '(pins 5,6,an7 on the LM75 tied to > ground) The good controll byte is the 01001000 it says on the lm75 data sheet that it is 1001xxx where the x's are pins 5-7. ahh I see now I added the extra 0 to the wrong end to get 8 bits right. > Ryan, there is only 4 registers in the LM47 47? its a 75 :) > 00000000=temperature reg. > 00000001=conmfiguration reg. > 00000010=T_hyst > 00000011=T_os what are these for?(T_hyst,T_os) > So, if you would like to read the temperature your address is 0 . > You can read 8 bites of the temperature register with the following > program. > symbol con=%01001000 OK > symbol addr=b2 what does b2 stand for? is this the variable it is stored in? > symbol temp=b0 what does b0 stand for? is this the portb.o pin? sorry Im still learning this stuff :) > addr=%00000000 OK > I2cin con,addr,temp OK > Unfortunatelly the Pbasic compiler can't read the 16 bit from the > LM75 so we loose the two lsb bits( I think). > If we want to get the another 8 bits we have to ask the listers to > help us (please). hmm someonesaid to me something about useing 9 bits and looseing a little accuracy , duno what though.(bad memory) regards, Ryan Pogge

> Van: Jeff Dickson <spam_OUTdicksonTakeThisOuTMICRO.CALTECH.EDU> > Aan: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU > Onderwerp: Re: newbie, pic basic > Datum: dinsdag 28 juli 1998 22:17 > > The latest Borland (inprise) C++ stuff lets you do 16 bit apps. > Let's upgrade, so we can get away from that DOS box and maybe > get some reasonably intelligent code. Placing a 747-airplane's cockpit-controlls in a truck does not make the truck more intelligent. It just gets more shiny lights & buttons to press. (refering to Win?? ontop of DOS) Who does not know the "blonde" jokes : Nice to look at, but no intelligence. :-) Greetz, Rudy Wieser

Hi, > ahh I see now I added the extra 0 to the wrong end to get 8 bits right. Yes Sir. > > Ryan, there is only 4 registers in the LM47 > 47? its a 75 :) Of course 75 I did a mistake. > > 00000000=temperature reg. > > 00000001=configuration reg. > > 00000010=T_hyst > > 00000011=T_os > what are these for?(T_hyst,T_os) There is an output pin in the LM75 called Overtemperature Shoutdown. If temperature is over than the data in the OS resister the OS pin is goes low according to the power up default. The T_hyst is the hysteresis register. If the temperature less then OS-Thyst the OS pin goes high. > > symbol addr=b2 > what does b2 stand for? is this the variable it is stored in? I put the address into a variable because we can change the address from 0 to 3 > > symbol temp=b0 > what does b0 stand for? is this the portb.o pin? sorry Im still learning > this stuff :) It's not the port B pin. The b0 is a variable which stores the temperature. > > Unfortunatelly the Pbasic compiler can't read the 16 bit from the > > LM75 so we loose the two lsb bits( I think). > > If we want to get the another 8 bits we have to ask the listers to > > help us (please). > > > hmm someonesaid to me something about useing 9 bits and looseing a little > accuracy , duno what though.(bad memory) Yes, we loose only one bit. The lsb is a 0.5 Celsius but the 1 celsius accuracy is a not too big deal. regards, George