Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!fernwood!portal!cup.portal.com!kize From: kize@cup.portal.com (Brian L Kaisner) Newsgroups: comp.graphics Subject: Re: 32768 colors with the TSENG ET 4000 and Sierra DAC ??? Message-ID: <43190@cup.portal.com> Date: 12 Jun 91 02:24:38 GMT References: <1991Jun6.191849.5312@vax5.cit.cornell.edu> <1991Jun7.172322.86856@vaxc.cc.monash.edu.au> Organization: The Portal System (TM) Lines: 17 First of all, replacing the existing DAC on a VGA board with a Sierra DAC probably won't work. I don't remember if the pinouts of the Sierra part are the same a the DACs typically used on a SVGA board. I _do_ recall that the Sierra part has monitor detection circuitry built-in, whereas DACs a year or more old require external comparators. I do know the Sierra part looks just like a regular VGA DAC until it receives certain commands from the VGA controller (Tseng in the current discussion) that put it into Hi-Color mode. The VGA controller then feeds the data into the DAC in the appropriate format on the rising and falling edge of the clock going to the DAC (twice the normal rate). That's all I remember off the top of my head. The more I think about it, the chances of a "DAC swap" working are very small, unless your board has jumpers to select such a manuever. Contact the board vendor ... - Brian