Saturday, January 25, 2014

Meet a Better Video Card - The Prolink Systems, Inc. MVGA-AVGA4VL VLB Card

Recently, I found a card nearly identical to this one from http://www.vgamuseum.info/ in an old system and decided to try it out :



I have tried it out and have come to like it more than my S3-805 based Diamond Stealth VLB card.  Its slightly faster, more compatible, supports more RAM and video modes.  I have no complaints about the DOS video quality.  It uses the Cirrus Logic CL-GD5429, which supports true color modes and Windows acceleration.  It uses memory-mapped I/O for increased speed.  It comes with 1MB of RAM and can be upgraded to 2MB with two 256x16-70ns Fast Page Mode SOJ chips.

The card has two jumpers, JP1 when closed allows for IRQ2/9 usage, and JP2 when closed allows for operation when the bus speed is greater than 33MHz.  The data sheet for the family of VGA controllers, for which this is perhaps its most advanced member, is readily available.  It reports that the card's BIOS supports the following SVGA/VESA modes :

14h - 132x25T
54h/10Ah - 132x43T
55h/109h - 132x25T
5Eh/100h - 640x400x256
5Fh/101h - 640x480x256
58h,6Ah/102h - 800x600x16
5Ch/103h - 800x600x256
5Dh/104h - 1024x768x16i/p
60h/105h - 1024x768x256i/p
6Ch/106h - 1280x1024x16i 
6Dh/107h - 1280x1024x256i*
66h/110h - 640x480x32K
64h/111h - 640x480x64K
71h/112h - 640x480x16M
67h/113h - 800x600x32K
65h/114h - 800x600x64K
68h/116h - 1024x768x32Ki
74h/117h - 1024x768x64Ki

* - Requires 2MB of video RAM.
i - Interlaced Mode
T - Text Mode

This card has better compatibility that the S3 card.  EGA compatibility is very good.  Commander Keen 4, 5 and 6 and Dangerous Dave do not need the SVGA compatibility switch, Keen 1-3 and Keen Dreams do not have scrolling problems, SimCity's text fonts look correct in the EGA high resolution mode and there are almost no flickering lines in the Silpheed intro.

VGA and SVGA compatibility is outstanding.  System Shock CD allows the 640x400 mode to be used, although the speed on my 486DX2/66 is not the speed at which I would like to play the game.  It has no problem with games with unusual Mode-X VGA modes like 320x240 (Epic Pinball), 320x400 (System Shock CD), 320x199 (Jazz Jackrabbit), 360x350 (Pinball Illusions), 312x200 (Prehistorik 2), 320x184 (Jurassic Park) and 320x350 (Pinball Fantasies).  It supports SVGA 640x480 and 800x600 resolution modes in Pinball Illusions perfectly.  It works with Prehistorik 1 & 2, Duff and Lollypop, both of which use a tweaked 320x200 mode.  It is among the supported 640x400 SVGA modes of Microsoft Flight Simulator 5.x.  It can even support the old Paradise SVGA 800x600 mode that Wonderland uses.  DOOM and DOOM II run just as fast on this card as the S3 card.

The DOS refresh utility is called CLMODE and there are Windows 3.1 drivers for the chipset.  The BIOS revision on my card is 1.00A.

Prompted by a friend of mine, I decided to perform a more demanding test, namely testing this card's support with UniVBE 5.3 and 6.53.  UniVBE 6.53 reports that Linear Frame Buffer will not work reliably with CL 542x chips with more than 14MB of RAM.  Support for LFB was thus dsiabled in my system, but 16MB of system RAM is more useful in a 486 than 12MB of system RAM and LFB.  With 8MB of RAM, UniVBE will install LFB at 14MB.  UniVBE also reports that Multi Buffering and Virtual Scrolling are also available, but 8-bit DACs are not present.

The card supports lots and lots of modes with UniVBE loaded, so I didn't test each and every resolution at each and every frame rate.  With UniVBE 5.3 all the modes I tested worked.  There are more modes supported with UniVBE than with the card's BIOS, and UniVBE offers superior compatibility with some modes than the BIOS alone.  UniVBE requires 13KB of RAM and it may not be possible to load it into upper memory, so it should only be used when necessary.  Here are the list of modes the card supports with UniVBE loaded :

4-bit Banked Only
640x480
800x600
1024x768

8-bit Banked and Linear
320x200
320x240
400x300
320x400
320x480
512x384
640x350
640x400
640x480
800x600
1024x768
1152x864

15-bit Banked and Linear
320x200
320x240
400x300
320x400
320x480
512x384
640x350
640x400
640x480
800x600

16-bit Banked and Linear
320x200
320x240
400x300
320x400
320x480
512x384
640x350
640x400
640x480
800x600

24-bit Banked and Linear
320x200
320x240
400x300
320x400
320x480
512x384
640x350
640x400
640x480

32-bit Modes
None

6 comments:

keropi said...

How does it behave with UNIVBE? Does LFB works with 16MB ram?

Great Hierophant said...

I added some more info the post, I hope it answers your question.

keropi said...

thanks for testing but SDD5 is not a good way to know if LFB actually works... if you use a newer SDD 6x version you get a message when you run UVCONFIG saying that previous versions enabled LFB but the CL chips had a fault and that led to random lockups...
I should have mentioned to try with SDD6 and see what it reports, sorry for that... SDD6 is freeware now, IIRC I posted it on VOGONS DRIVERS

Greg Soravilla said...

I was a Cirrus Logic junkie back in the mid 90s. I remember pushing these chips past their listed resoluions using Linux. I recently found one of my old Cirrus Logic books "Alpine VGA Family CL-GD543X/'4X Technical Reference Manual February 1995". It describes timings, registers, etc. No idea where I originally got it. Great stuff!

Anonymous said...

There is one disappointment with the CL-GD5428 with BIOS v1.41: It does not support graphics mode 100h (640x400x8) without the Univbe TSR.

Does you CL-GD5429 fare better in this regard?

Regards, Gerwin

Great Hierophant said...

I do not believe that the LFB really works after all with this card, but I think my motherboard is dying and the card crashes with many tests which it had previously passed.

I am virtually positive that this card supports 640x400x8, because System Shock CD will run in that mode (just not very fast).