From owner-freebsd-hackers Sun Nov 2 08:21:13 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id IAA28666 for hackers-outgoing; Sun, 2 Nov 1997 08:21:13 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from dfw-ix5.ix.netcom.com (dfw-ix5.ix.netcom.com [206.214.98.5]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id IAA28656 for ; Sun, 2 Nov 1997 08:21:05 -0800 (PST) (envelope-from wghhicks@ix.netcom.com) Received: (from smap@localhost) by dfw-ix5.ix.netcom.com (8.8.4/8.8.4) id KAA00415 for ; Sun, 2 Nov 1997 10:20:29 -0600 (CST) Received: from atl-ga9-17.ix.netcom.com(199.183.210.113) by dfw-ix5.ix.netcom.com via smap (V1.3) id rma000069; Sun Nov 2 10:18:41 1997 Message-ID: <345CA7BE.B8E3E25B@ix.netcom.com> Date: Sun, 02 Nov 1997 11:18:06 -0500 From: Jerry Hicks Reply-To: wghhicks@ix.netcom.com Organization: TerraEarth X-Mailer: Mozilla 4.03b8 [en] (X11; I; FreeBSD 2.2.5-STABLE i386) MIME-Version: 1.0 To: hackers@FreeBSD.ORG Subject: Re: 7400 gates effected by probe routine References: <345C87C9.15FB7483@est.is> Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Þorður Ivarsson wrote: > > I am not sure at the moment but I have been working with Rocwell 6522 > PIA and > I think it should be possible to probe 8255 in same manner as 6522, send > byte to > output ports and read back, if they are defined as output you should get > the > same back out from them. I think you can also with the control register. > > Do you have the 8255 datasheet ? it is available from Intel website > > -- > Þórður Ívarsson Thordur Ivarsson > Rafeindavirki Electronic technician > Norðurgötu 30 Nordurgotu 30 > Box 309 Box 309 > 602 Akureyri 602 Akureyri > Ísland Iceland > > --------------------------------------------- > FreeBSD has good features, > Some others are full of unwanted features! > --------------------------------------------- FWIR, you can't read the outputs back from a simple buffered 8255. We designed a board once with a registered PAL to front-end the 8255 for that function. Good Luck, Jerry Hicks jerry_hicks@bigfoot.com