Date: Sun, 14 Apr 1996 19:00:44 +0000 From: Poul-Henning Kamp <phk@critter.tfs.com> To: dk+@ua.net Cc: freebsd-hardware@FreeBSD.org Subject: Re: building parallel interface gadget - advice wanted Message-ID: <20335.829508444@critter.tfs.com> In-Reply-To: Your message of "Sun, 14 Apr 1996 19:47:41 %2B0300." <199604141647.TAA08085@clipper.cs.kiev.ua>
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> My only question is: > > from my understanding, for the data byte t obe output into the (real) > printer, it is necessary to assert select, !initialize and strobe > bits of control register and then lower the signal on the strobe pin, > leaving select and !initialize high. Can it be possible that the > same situation unwantedly occurs during system reset (power-on, reset > by switch, software-executed reboot, etc.)? Not only possible, but also very likely. The parallel port is used by man BIOS's as a status port for diagnostics early in the boot sequence. You should protect yourself from this by encapsulating your commands in something very unlikely like "jH#@@'" -- Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team. http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox. whois: [PHK] | phk@ref.tfs.com TRW Financial Systems, Inc. Future will arrive by its own means, progress not so.
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