ISA Super VGA

Overview

The ISA Super VGA card is based on the Trident TVGA9000i Super VGA controller IC. It offers excellent compatibility with the original IBM VGA, as well as a good emulation of older CGA, EGA, Hercules and MDA adapters. The ISA Super VGA card was designed to be used with the Xi 8088 Processor Board, but it also works in IBM PC/XT and their clones. It will work in 16-bit ISA slots of AT-compatible computers, but its performance will be inferior to 16-bit VGA cards.

Note: PCB Version 1.0 requires a rework for compatibility with the original IBM PC and IBM XT computers, please see the Errata section below. This errata was fixed in the PCB Version 1.1

Picture

Specifications

Supports 256 KiB or 512 KiB video memory using two or four 256 Kbit x 4 DRAM ICs.
8088-friendly VGA BIOS.
Only 6 ICs (SVGA IC, BIOS, four DRAM chips), some capacitors, resistors and inductors.

Bill of Materials

Component Type	Reference	Description	Quantity	Possible sources and notes
PCB		ISA Super VGA PCB	1	Refer to the RetroBrew Computers Board Inventory page for ordering information, or order from a PCB manufacturer of your choice using provided Gerber or KiCad files. Here is OSH Park project link.
Integrated Circuit	U1	Trident TVGA9000i-3	1	Utsource or other component dealers. Other TVGA9000i versions can be used (e.g. TVGA9000i-1)
Integrated Circuit	U2	27C256 UV erasable EPROM or OTP ROM	1	Unicorn Electronics, Jameco, Mouser (OTP ROM)
Integrated Circuit	U3 - U6	Micron MT4C4256, Motorola MCM514256, or similar 256 Kbit x 4 DRAM, 70ns or less	2 or 4	Unicorn Electronics Install 4 for the total memory of 512 KiB or two for 256 KiB
Capacitor	C1 - C12	0.1 uF ceramic, 5.08 mm pitch	12	Mouser 810-FK28X7R1H104K
Capacitor	C13 - C16	10 uF, 16V, multilayer ceramic or tantalum, 5.08 mm pitch	4	Mouser 810-FK24X5R1C106K
Capacitor	C17	1 nF ceramic, 5.08 mm pitch	1	Mouser 810-FK28C0G2A102J
Capacitor	C18	470 pF ceramic, 5.08 mm pitch	1	Mouser 810-FK28C0G1H471J
Capacitor	C19	100 pF ceramic, 5.08 mm pitch	1	Mouser 810-FK28C0G1H101J
Capacitor	C20 - C27	47 pF ceramic, 5.08 mm pitch	8	Mouser 810-FK28C0G1H470J
Resistor	R1 - R8	4.7 k, 1/4 W	8	Mouser 291-4.7K-RC
Resistor	R9	1 k, 1/4 W	1	Mouser 291-1K-RC
Resistor	R10 - R13	150 Ohm, 1/4 W	4	Mouser 291-150-RC
Resistor	R14	100 Ohm, 1/4 W	1	Mouser 291-100-RC
Resistor	R15, R16	33 Ohm, 1/4 W	2	Mouser 291-33-RC
Connector	P1	DE15F, right angle PCB mount	1	Mouser 806-K66X-E15S-NJVESA, 571-1-1734344-1 (blue color), 806-K66X-E15S-NJ30
Connector	JP1	2 pin header	1	Mouser 649-68002-102HLF
Inductor	L1, L3	5.7 uH	2	Mouser 542-78F5R6J-RC
Inductor	L2	2.7 uH	1	Mouser 542-78F2R7-RC
Filter	FB1 - FB6	EMI Filter Bead	6	Mouser 623-2743001112LF
Crystal	X1	40 MHz	1	Mouser 815-ABL-40-B2
IC Socket	U2	28 pin 600 mil (wide) DIP socket	1	Mouser 517-4828-6000-CP
IC Socket	U3 - U6	20 pin 300 mil (narrow) DIP socket	4	Mouser 517-4820-3000-CP
Bracket		ISA card bracket - Keystone 9200-1	1	Mouser 534-9200-1

Changes

Version 1.1

Fix ALE errata. ALE signal is now connected to 5V
Slightly move VGA DE-9F connector (about 1.27 mm up and 0.8 mm back) to better comply with ISA card size and bracket placement specifications

Version 1.0

Minor board modifications around JP1

Errata

Version 1.0

The original IBM PC, the original IBM XT, and XT clones that closely follow IBM XT schematic do not implement the ALE signal properly. In these computers the ALE signal occasionally activated during DMA cycles, for example during memory refresh, while the address on the address bus is invalid. This confuses the Trident TVGA controller. The following rework is required to make ISA Super VGA work in these computers: The TVGA9000 ALE signal needs to be disconnected from the ISA ALE signal, and connected to the 5V power signal. The photo below shows such modification (photo credit: keropi at VCF forum).

ISA SVGA - Board - 0.9.pdf

(479k)

Sergey Kiselev,

Apr 5, 2013, 8:30 PM

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