The Cyber-Spy.Com Usenet Archive Feeds Directly
From The Open And Publicly Available Newsgroup
This Group And Thousands Of Others Are Available
On Most IS NNTP News Servers On Port 119.
Cyber-Spy.Com Is NOT Responsible For Any Topic,
Opinions Or Content Posted To This Or Any Other
Newsgroup. This Web Archive Of The Newsgroup And
Posts Are For Informational Purposes Only.
From: "N. Coesel"
Subject: Re: Urgent help needed to blank monitor
Date: Wed, 6 Nov 2002 11:02:20 +0100
Organization: Planet Internet
References: <email@example.com> <2fMx9.160$tQ1.firstname.lastname@example.org>
NNTP-Posting-Date: 6 Nov 2002 10:03:50 GMT
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
"Ulrich Peters" wrote in message
> Hello again.
> I think it might be best to expect a certain bit pattern on the parallel
> port, to get one logical high (or low) to control the circuit, because
> the serial port is already in use by a bill acceptor, and the sound card
> is used to provide acustical feedback to the user during the normal
> operation of the software.
> Although a 555 timer could be used to create a delay to switch on the
> monitor, I prefer to use the parallel port solution, because I would
> have control over the shutdown process as well. The equipment has a
> button on its back to power down the equipment. Before my software shuts
> down, the last thing it could do is quickly send a new byte to the
> parallel port, turning off the monitor, before Windows shows its usual
> shutdown dialogs ("saving settings", "closing connections", etc.).
> Unless you send new data to the parallel port, the last byte sent
I wouldn't rely on that. I've made an eprom emulator connected to a parallel
port. Bit banging seemed not to work because the last byte didn't always
'stick' (I didn't lock the printerport). For this reason I made my eprom
emulator mimic a printer port. This is fairly easy. If you have a latch
(like a 74HCT573 or a 74HCT574) and clock it from the strobe line, you can
simply send printer output to your circuit. If you take 2 comparators (like
74HCT688) you can select an on-character and an off-character. The
comparators's outputs should be connected to a flipflop with (pre)set and
clear inputs (like 74HCT74).
Reply to: nico nctdev nl @ .
Go Back To The Cyber-Spy.Com
Usenet Web Archive Index Of
The sci.electronics.design Newsgroup