First post, by mkarcher
I recently got my hands on an EIZO branded graphics card. While this company is best know for their monitors, they also sold graphics cards. For example, EIZO had the AA40, which is displayed as one of the C&T 82C480 based 8514/A clones. That card seems to be a straight-forward implementation of the basic 82c480 design idea. The card I recently saw seems to have no photos on the internet yet, so it's time to fix that!
This is the successor, the AA41. It differs from the AA41 by being twice as good (measured in PCB area). No, just kidding. It differs from the AA41 by actually extending the architecture. The 82B484 chip responsible for sending the VRAM data to the DAC has been replaced by a custom ASIC with a "spectragraphics" copyright, which is named FFC ASIC by EIZO. This is an abbreviation for "flicker-free cursor". It provides a hardware mouse cursor. This function is integrated in many more sophisticated DAC chips, like the Bt485, but if I understand the documentation correctly, the 6288 16K x 4 SRAM next to the "FFC ASIC" can contan a 256-color 64x64 mouse cursor, whereas the usual "hardware cursor" feature is usually limited to a three-color, or two-color/invert cursor.
Furthermore, there are two further ASICS. This card is claimed to have a local video memory bus, called the GS bus. The "IF" ASIC implements the ISA bus interface, and adds some extra features, like a deeper command word FIFO. The original 8514/A had an 8 word FIFO, and this card is claimed to extend that to 80 bit-blit commands, each of them consisting of multiple words. The second ASIC is called the "DE" ASIC (for "data engine") and implements a drawing engine. While the 8514/A already has an internal drawing engine, the DE ASIC is claimed to provide an arbitrary 3-operand drawing function implementation, which is not present in the 8514/A. This has possibly been added to aid with implementing the MS GDI architecture.
The card is delivered with two feature-connector cables, one for VGA cards with a pin-header feature connector, and a second one for VGA cards with a card-edge feature connector.
The for chips in the center are the main video RAM. The 8514 architecture accesses words of multiple pixels at the same time. All the pixels inside a word are collectively called a nugget. A 8514/A nugget can consist of 4 or 5 pixels, and the video memory is organized as 256 nuggets per line. This card has 4 VRAM chips, each storing one of the pixels in a nugget, so it uses 4-pixel nuggets, and a screen width of 1024 pixels. There is a 5-pixel-nugget variant of the card, the AA51, which supports a screen width of up to 1280 pixels. (See later post for correct info on the AA51) The RAM chips on the card are 4 bits wide, so the card is limited to 16 colors (at the full resolution), as long as the optional memory upgrade module is not installed. The memory upgrade module adds 4 bits to each pixel in the nugget, upgrading it to a 256-color card at 1024x768.
I also got the 5.25" floppy disks and the software installation manual of that card.
I'm sorry for the excessive sharpening artifacts on the floppy drive labels. I didn't notice the over-sharpening of the mobile phone camera when I took those shots.
See the next post for the contents.
