Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!hp-pcd!hpsgwp!plim From: plim@hpsgwp.sgp.hp.com (Peter Lim) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: Upgrading 256K VGA to 512K VGA card Message-ID: <3370003@hpsgwp.sgp.hp.com> Date: 28 Dec 90 07:20:27 GMT References: <62M^M8#@rpi.edu> Organization: HP Singapore IC Design Ctr Lines: 29 / phil@brahms.amd.com (Phil Ngai) / 3:35 am Dec 27, 1990 / writes: > > Wrong. I know (intimately) at least one (Super) VGA chipset that offers a > 16-bit interface to the ISA bus using only two 256Kx4 RAM chips. How do > they do it? Think about it... > Two 256Kx4 RAM chips only give you 256K x 4 / 8 = 128K byte RAM. Is that enough to qualify it as superVGA ? Considering SuperVGA means at least 640 x 480 x 256 colors => 640 x 480 bytes = 300 Kbytes ! >> 128 Kbytes. That aside, assuming you have two 256Kx4 chips. That means that you can only write 8 bit in one time into those two chips. Other than inserting wait state and do the 16 bit write from the bus as two 8 bit writes on the VGA board, I don't see how you can do full 16 bit write. Not that most VGA card don't insert wait state :-). If it is done any other way, can you let us know ? Regards, . .. ... .- -> -->## Life is fast enough as it is ........ Peter Lim. ## .... DON'T PUSH IT !! >>>-------, ########################################### : E-mail: plim@hpsgwg.HP.COM Snail-mail: Hewlett Packard Singapore, : Tel: (065)-279-2289 (ICDS, ICS) | Telnet: 520-2289 1150 Depot Road, __\@/__ Singapore 0410. SPLAT ! #include