Professional Graphics Controller

Software support

The board was targeted at the CAD market, therefore limited software support is to be expected. The only software systems known to support the PGC are IBM's Graphical Kernel System, P-CAD 4.5, VersaCAD, Canyon State Systems CompuShow and AutoCAD 2.5.

Output capabilities

PGC supports:

• ** with 256 colors** from a palette of 4,096 (12-bit RGB palette, or 4 bits per color component).
• Color Graphics Adapter text and graphics modes. Text modes use a font with 8×16-pixel character cells and have 400 rows of pixels.

There are six possible color arrangements:

• Default 256-colour palette - Low 4 bits intensity, high 4 bits colour;
• 16-colour palette - Makes the PGC behave as two 16-colour planes. If high 4 bits are 0, low 4 bits are colour; otherwise, high 4 bits are colour;
• 2-3-3 palette (Palette 2) - Bits 6-7 red, bits 3-5 green, bits 0-2 blue;
• 3-2-3 palette (Palette 3) - Bits 5-7 red, bits 3-4 green, bits 0-2 blue;
• 3-3-2 palette (Palette 4) - Bits 5-7 red, bits 2-4 green; bits 0-1 blue;
• 6x6x6 colour cube - six equally spaced shades of red, green, and blue.

Operation

The display adapter was composed of three physical circuit boards (one with the on-board microprocessor, firmware ROMs and video output connector, one providing CGA emulation, and the third mostly carrying RAM) and occupied two adjacent expansion slots on the XT or AT motherboard or the Expansion Unit; the third card was located in between the two slots. The PGC could not be used in the original IBM PC without the 5161 Expansion Unit due to the different spacing of its slots.

In addition to its native mode, the PGC optionally supported the documented text and graphics modes of the Color Graphics Adapter, which could be enabled using an onboard jumper. However, it was only partly register-compatible with CGA.

Related monitor

The PGC's matching display was the IBM 5175, an analog RGB monitor that is unique to it and not compatible with any other video card without modification. With hardware modification, the 5175 can be used with VGA, Macintosh, and various other analog RGB video sources. Some surplus 5175s in VGA-converted form were still sold by catalog retailers such as COMB (Close Out Merchant Buyers) as late as the early 1990s.

Hardware clones

• Matrox PG-640, PG-1280 and QG-640 (for the DEC MicroVAX)
• Dell NEC MVA-1024 card
• Everex EPGA
• Orchid Technology TurboPGA
• Vermont Microsystems IM-640, IM-1024

References

;Notes

• Mueller, Scott (1992) Upgrading and Repairing PCs, Second Edition, Que Books, - which says 3 slots and "adapter"
• A Professional Graphics Controller by K. A. Duke and W. A. Wall, IBM Systems Journal

References

1. (August 15, 1984). "IBM Personal Computer Professional Graphics Controller Technical Reference". lBM Corporation.
2. Elliott, John. (August 11, 2010). "Professional Graphics Controller Notes". John Elliott's homepage.
3. (10 September 1984). "Announcement Letter Number 184-112 dated September 10, 1984: IBM 5175 PERSONAL COMPUTER PROFESSIONAL GRAPHICS DISPLAY AND PERSONAL COMPUTER PROFESSIONAL GRAPHICS".
4. (1983-06-07). "Announcement Letter Number 183-082 dated June 7, 1983: IBM PERSONAL COMPUTER AND IBM PERSONAL COMPUTER XT ENHANCED WITH ANNOUNCEMENT OF MATH CO-PROCESSOR".
5. "CompuShow History".
6. Milburn, Ken. (September 29, 1986). "Autocad ADE-3, Version 2.5". InfoWorld.
7. R., Bill. "The IBM PGA Graphics Adapter".
8. "Google Discussiegroepen".
9. Vlask. "NEC MVA 1024".
10. Elliott, John. (August 11, 2010). "Professional Graphics Controller Notes - Clones".
11. "Orchid Turbo PGA". Orchid Technology.
12. (September 22, 1986). "Image Manager 1024 advert". InfoWorld.