Article View: comp.sys.ibm.pc.misc
Article #3894Re: Need to know about a few CGA ports
From: halco
Date: Fri, 12 Oct 1990 18:19
Date: Fri, 12 Oct 1990 18:19
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1125 bytes
In article <90267.162100II70038@MAINE.BITNET>, II70038@MAINE.BITNET (Jonathan Kimball) writes: > Could someone tell me what ports or registers on the CGA card are used to: > 1. Determine if the card is in vertical(not horizontal) retrace. > 2. Enable/Disable blinking. > 3. Enable/Disable underscore. VSYNC is indicated by a "1" at bit 00001000, port 3DAH. Blinking is enabled by setting bit 00100000, port 3D8H. You must set the blink bit (10000000) in the attribute byte of each character you want to blink. This also forces the background color of all characters to be the same. As far as underlining, I don't think it can be be done on CGA. Have fun. Bruce Halco > > Jonathan Kimball > II70038 at MAINE.BITNET
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!tut.cis.ohio-state.edu!abvax!iccgcc!halco From: halco@iccgcc.decnet.ab.com Newsgroups: comp.sys.ibm.pc.misc Subject: Re: Need to know about a few CGA ports Message-ID: <1426.2715c2df@iccgcc.decnet.ab.com> Date: 12 Oct 90 18:19:27 GMT References: <90267.162100II70038@MAINE.BITNET> Lines: 21