One Wire from Pic

[bryan]

Hmm, dumb question here, but can I create a one wire application from a pic/avr, in other words can I code a pic/avr so that it behaves like say a DS18B20 sensor and then strung in series with other one wire sensors.

 

[Pommie]

I'm sure that you can but it wouldn't be trivial. The main difficulty would be the requirement to get the data on the bus 6uS after the master pulled the bus low however, I believe this could be stretched to 10-12uS as the master doesn't sample until 15uS. Also, the ROM Search function would be a challenge to implement.

I've thought of having a go myself a few times.

Mike.

 

[be80be]

I thought of this myself and the show stopper was the "Rom search" I never could get a handle on how to make that work.

I wanted to have some code i could run and use for testing one wire devices that I could change into what I wanted it to be.

maybe I'll try agin. Burt

 

[Pommie]

I'm now thinking that the Romsearch function wouldn't be to hard to implement. It's a normal read slot with a sample taken at 15uS and if the sample doesn't match what you outputted then you go to sleep until the next reset occurs. I'm now starting to think that it might be very doable with a 12F683 using the 8MHz internal oscillator. If I get time I might have a play with this at the weekend.

Mike.

 

[bryan]

Seems it's not a easy task, if you folks think it's difficult, I don't think i stand a chance <g>

 

[magnatro]

good decision

 

[dougy83]

Seems it's not a easy task, if you folks think it's difficult, I don't think i stand a chance <g>

It's not so hard. You might as well give it a try.

 

[bryan]

Looks like this chip from maxim does the same

**broken link removed**