Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!mcvax!kth!sunic!dkuug!freja!rimfaxe!dearwolf From: dearwolf@rimfaxe.diku.dk (Mikael C. Kj{rulff) Newsgroups: comp.sys.ibm.pc.rt Subject: Re: more than 16 levels of grey on a 5081 (megapel) using Xwindows Message-ID: <4591@freja.diku.dk> Date: 12 Apr 89 12:48:23 GMT References: <22690@shemp.CS.UCLA.EDU> Sender: news@freja.diku.dk Lines: 40 wine@maui.cs.ucla.edu writes: > We'd like to use our 5081 as a display device for images using Xwindows, > but we can only get 16 levels of grey out of it. Is there any way > to get 256 levels of grey (hardware, and/or software)? I had the same problem, but IBM-Denmark got hold of a new version of the Color Palette chip for the Megapel Adapter cards. The new version have a 3 x 8 bit entry (instead of 3 x 4) for each color to lookup, giving 256 greylevels at your Megapel (and is faster?). As far as I understand only X11 (AIX/RT X-Windows V2.1) running under AIX 2.2.1, knows how to make use of all the 24 bits in the Color Palette. I got hold of some test programs (from IBM) which left no doubt that the upgrade worked. I haven't yet tried it with X11, while I am waiting (and waiting (and waiting...)) for NFS, before I will upgrade to AIX2.2.1 and AIX/RT X-Windows V2.1. Below a short description of the hardware upgrade, as I made it: Prev : Bt451KG100 RAMDAC New : Bt458KG125 RAMDAC Location: At the Megapel-controller card (the bottom one of the two cards of the Megapel adapter) near the outlet for the RGB-signals, grey, 3 cm square, (~ 1.25"). NOTE the writing at the chip is upside down (if you have the RGB-outlet to your right). Replace the chip and make sure the writing turns out upside down. Note that it does *NOT* sit directly on the socket, there is a small (~ 1 mm.) space of air between them. Have fun, but be aware: the cards/chips are STATIC SENSITIVE DEVICES! -- dearwolf@diku.dk Mikael C. Kjaerulff Department of Computer Science, University of Copenhagen, Denmark