> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On
Behalf
> Of PICdude
> Sent: 23 September 2010 14:58
> To: piclist@mit.edu
> Subject: [EE] Implementing 1-wire slaves
>=20
> Sometime years ago, I had heard (IIRC on this forum) that 1-wire
> technology is patented, such that I can't implement my own slaves.
> I've not come up with the patent yet, and Maxim hasn't responded to me
> yet.  Anyone know if this is true, if the patent is still valid, and
> what the general details are?
>=20
> I want to bi-directional communication to a PIC application, and have
> only 1 wire available.  I also have no room for additional (1-wire
> slave) chips, but that would be pointless anyway as that slave chip
> would need more than one wire for communicating with the PIC.
>=20
> If this is not doable, I may end up rolling my own protocol that can
> work with a single wire, but I'd need to know what specifically is
> patented with respect to 1-Wire technology.

You can do simplex UART comms over a single wire if you drive the wire
with an open collector type interface.  Obviously the USART which is
transmitting on the bus also receives it's own data, so it's relatively
easy to detect collisions on a byte level (or bit level if you bit bash
the UART).

Regards

Mike

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