Hello,

If this is a one-of-a-kind product, you could just attach each device to the
bus one at a time, get its address, and then write it down.  You can now
hardcode the three address into your program and don't have to worry about
dynamically determining who is on the bus and what there serial numbers are.
This solution is ideal, IMHO, for a one-of-a-kind project where devices will
not be dynamically added/removed from the bus.

Donovan Parks


> Thanks for the reply Tony
>
> Up until now I've been using a single 1wire device and the ccs c
> compiler.
> I can read, write, get its address and do a crc on the data.
>
> Now, I want to talk to multiple devices.  I have added  3 devices on the
> bus to experiment with. I want to read the serial number of each at
> power
> up and then individually address them. The problem is getting their
> serial
> numbers(addresses)
>
> I've read and re-read the dallas datasheet 187 '1 wire search
> algorithm',
> but can't get the code to work, I'm sure this is a hole in my
> understanding
> not in the dallas example code, but I can't help thinking theres a
> 'neater'
> ie shorter, quicker way of doing it.
>
> Regards
>
> Steve
>
> Tony Nixon wrote:
>
> > Tony Nixon wrote:
> >
> > I forgot to mention that this will only work for 1 device on the bus
> at
> > a time. There is a much more complicated procedure to use if multiple
> > devices are on the bus and need identification, but I haven't used
> that
> > method yet.
> >
> > > This is in assembler, but perhaps you can port it to C without much
> > > bother.
> > >
> > > Data in buffer after execution = 8 bytes
> > >
> > > Family Code - 1 byte
> > > ID Number   - 6 bytes
> > > CRC         - 1 Byte
> > >
> > >         movlw Buffer            ; set buffer pointer
> > >         movwf FSR
> > >         call INITDS             ; start new transaction
> > >         Send_Out Read_ROM       ; read ROM command
> > > GIDLoop call IN_BYTE            ; read bytes
> > >         movwf INDF
> > >         incf FSR
> > >         movlw Buffer + d'8'
> > >         xorwf FSR,W
> > >         btfss STATUS,Z
> > >         goto GIDLoop
> > >         return
> >
> > --
> > Best regards
> >
> > Tony
> >
> > mICros
> > http://www.bubblesoftonline.com
> > mailto:sales@bubblesoftonline.com
> >
> > --
> > http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body
>
> --
> http://www.piclist.com hint: To leave the PICList
> mailto:piclist-unsubscribe-request@mitvma.mit.edu
>
>

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu