Subject: Re: Dallas semiconductor "one-wire" and envsys(4)
To: Jeff Rizzo <>
From: Gavan Fantom <>
List: current-users
Date: 02/27/2006 22:52:19
David Laight wrote:
> Is this the same interface as used in some of the battery gauge chips?
> Where you generate a square wave with a 25%-75% duty cycle (for 0 and 1),
> and where the device sends you data at its own clock speed that you have
> to follow and sample the midpoint (or time the high part) to work out
> whether it is sending a 0 or 1 ?
> If so you need a uart to generate the data and parse the response
> (or a dedicated PIC cpu to drive the gpio lines), you won't do it
> reliably from within a Unix kernel without completely stuffing anything
> else the system is trying to do.

Would high priority gpio pin change interrupts and high resolution 
timers not do the job here?

Gillette - the best a man can forget