From owner-freebsd-hackers Thu Apr 19 12:42:25 2001 Delivered-To: freebsd-hackers@freebsd.org Received: from critter.freebsd.dk (fw2.aub.dk [195.24.1.195]) by hub.freebsd.org (Postfix) with ESMTP id 8C28437B424 for ; Thu, 19 Apr 2001 12:42:21 -0700 (PDT) (envelope-from phk@critter.freebsd.dk) Received: from critter (localhost [127.0.0.1]) by critter.freebsd.dk (8.11.3/8.11.3) with ESMTP id f3JJfvU60548; Thu, 19 Apr 2001 21:41:57 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Warner Losh Cc: David Miller , freebsd-hackers@FreeBSD.ORG Subject: Re: [OT] parallel port for IO? In-Reply-To: Your message of "Thu, 19 Apr 2001 13:34:17 MDT." <200104191934.f3JJYH806407@harmony.village.org> Date: Thu, 19 Apr 2001 21:41:57 +0200 Message-ID: <60546.987709317@critter> From: Poul-Henning Kamp Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <200104191934.f3JJYH806407@harmony.village.org>, Warner Losh writes: >If you have only 1 source, then you can use the ack line of the >parallel port and the ppi driver to get timestamped events. If you >have more than one, then you might be able to wire a simple latch to >the ACK line and sample of to 8 sources. That's trickier as their's >some hair in converting the signals to pulses, worrying about races, >etc. 1 source gives you nanosecond resolution (but only ms accuracy >due to interrupt latencies, us if you hack it to be a fast interrupt). Use the pps driver and you get microsecond jitter with nanosecond resolution. The pps driver implements the RFC2783 PPS-API for timestamping external events. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message