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From: bryan@druhi.UUCP
Newsgroups: comp.sys.ibm.pc
Subject: Re: How does one enable the other 8 background colors
Message-ID: <1982@druhi.ATT.COM>
Date: Sun, 21-Jun-87 15:54:11 EDT
Article-I.D.: druhi.1982
Posted: Sun Jun 21 15:54:11 1987
Date-Received: Fri, 26-Jun-87 01:59:43 EDT
References: <292@qtc.UUCP> <1005@watmum.UUCP>
Organization: AT&T, Denver, CO
Lines: 26
Summary: Not quite true

In article <1005@watmum.UUCP>, smvorkoetter@watmum.UUCP writes:
> In article <292@qtc.UUCP> ed@qtc.UUCP (Ed Lisle) writes:
> >How does one enable the other background colors so one can have
> >16 forground/16 background colors in Microsoft C ?
> 
> I assume you are talking about the CGA on a PC or Clone.  If so, then
> you are out of luck.  There are only 8 background colours.  [More
> reiteration of this point deleted.]

This isn't quite true.  Bit 5 of the "Mode Select Register" of the 6845
CRT controller (used in the IBM CGA and many clones) selects blinking
versus 16 background colors.  Doing:

	MOV DX,03D8H
	OUT DX,009H

on an IBM PC with CGA will cause 80x25 color text mode to be selected
with 16 background colors and no blinking.  In this mode, setting what is
normally the "blink" bit will now intensify the background color, giving
you access to the other 8 background colors.  The ROM BIOS merely sets
bit 5 during the power-up initializations to enable blinking instead.
-- 
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John T. Bryan              USENET:  ...!ihnp4!druhi!bryan
AT&T Information Systems   PHONE:   (303) 538-5172
Denver, CO  80234