Date: Fri, 17 Jul 1998 09:39:38 +0930 From: Greg Lehey <grog@lemis.com> To: Servidor <medur@medur.es> Cc: FreeBSD Questions <questions@FreeBSD.ORG> Subject: Re: Programing in BSD Message-ID: <19980717093938.E566@freebie.lemis.com> In-Reply-To: <199807161449.QAA02968@ic.infase.es>; from Servidor on Fri, Jan 02, 1998 at 04:57:58PM %2B0100 References: <199807161449.QAA02968@ic.infase.es>
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On Friday, 2 January 1998 at 16:57:58 +0100, Servidor wrote:
> Hello!
>
> I'm student of computer science, and I have a little problem. I'm working
> with freeBSD and I must to program the UART. I have programed the UART in
> dos and linux, but I never do it in freeBSD.
Please don't send this kind of question to FreeBSD-doc, a mailing
list concerned with improving the documentation of FreeBSD. The
correct list is FreeBSD-questions.
> I don't know how i can access to a position of memory where a port of the
> UART is mapped, I would like to know wich libraries of freeBSD i must to
> use and wich instructions.
PCs normally don't memory map I/O devices, they address them via a
separate address space ("I/O space"). In UNIX (including Linux), the
UART is controlled by the system, so you don't "program the UART", you
write a driver. You'll find the source in
/usr/src/sys/i386/isa/sio.c.
If you really *do* want to access the I/O registers from user space,
an action which is strongly deprecated, open /dev/io. See io(4) for
(few) more details.
Greg
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