Date: Sun, 30 Sep 2001 17:38:21 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: Bart Kus <bsd@shell-server.com> Cc: hackers@FreeBSD.ORG Subject: Re: sio modification Message-ID: <3802.1001864301@critter> In-Reply-To: Your message of "Sun, 30 Sep 2001 10:10:04 CDT." <200109301003.06903@EO>
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In message <200109301003.06903@EO>, Bart Kus writes: > Hello, I'm wondering about a seemingly simple sio.c modification. The >problem stems from me wanting to use this dang remote control receiver, which >manipulates the CD line of the serial port it plugs into. Afaik, the UART >itself is capable of generating an interrupt whenever CD changes. The >problem is, sio.c doesn't support this feature. I'm stuck with polling the >status register to find out the state of CD. Not a very good solution for a >daemon that's supposed to run in the background all the time, especially >since the CD line will be toggled at about 40kHz (I think that's the remote >control frequency standard). Perhaps I'm wrong about the 40kHz figure. Your machine will not work too well if it is 40kHz. The PPS-API allows you to timestamp edges on DCD, if the frequency is more reasonable, that would work for you. Find RFC27xx for more info about PPS-API. -- 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
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