Unreleased Add Ons
To enhance and modernize the Aster CT-80 the company also designed three alternative video display adapters to supplement or replace the TRS-80 compatible video card, (due to the modular nature of the Aster it was simply a matter of changing the video card, and/or CPU card to upgrade the system).
- A very High resolution monochrome video card with blitter and hardware text line and arc drawing capability, was designed for CAD applications, based on the NEC µPD7220 chip designed for graphic terminals, but was also used by some personal computers like the DEC Rainbow, and notably also for the Tulip System I.
- A colour video card with sprite capability based on the same video chip (the TMS9918) as the TI99/4 and MSX computers, designed for gaming, and more creative and colorful educational software. A working prototype of this card was finished.
- A replacement card for the original TRS-80 compatible video card, software compatible to the original one, but with added color and very high resolution capabilities. was also on the drawing board. Based on a newer, slightly more flexible, version of the Asters original Motorola MC6845 video chip, the Rockwell 6545, it worked by adding a new video mode, one with the ability to reprogram an extended, (2048 characters instead of 256 characters) version of the character set, supported by an extended character memory of the video card that did not use one (8 bit) byte per character, but an 11 bit "word", so it could address each one of the available 2048 unique programmable characters. This meant it could provide a separate programmable character for all of the 1024 (64x16) or 2000 (80x25) characters on the screen. By filling the character pointer memory with values from zero to 1919 this essentially turned the text mode display into a very high resolution graphics mode, with the "font memory", acting as the high resolution Raster graphics video memory. Because the characters were 8 x 12 pixels this meant that video resolutions of 512 x 192 pixels (in 64x16 character mode), or 640 x 300 pixels (in 80x24 character mode) were created, which was quite high for the time. The "double width" mode of the TRS-80 was also supported, so 256 x 192 pixels (in 32x16 character mode), or 320 x 300 pixels (in 40x24 character mode) were also possible. The video card also supported 16 foreground and 16 background colors per character, by providing one byte per character position (2K) of "color ram". One nibble of such a byte then controlled the foreground color, and the other nibble controlled the background color, a system very similar to the Sinclair ZX Spectrum, in fact in the 256x192 mode the display mode was virtually identical to the video of the Sinclair ZX Spectrum. The color memory was also available in the "normal" TRS-80 and CP/M text modes, which meant that existing TRS-80 and CP/M software could be easily modified to add color. This video card would also support fast scrolling of high resolution color screens for games, because it had the indirection of the character pointers, so it was possible to quickly scroll the high resolution display, (or use other effects) by simply manipulating the 1920/1024 bytes of text video instead of the 24.576 bytes of high resolution video memory.
A hard disk interface was also in the works, which would, add a SCSI interface, and the necessary software. A working prototype was developed that added a 40MB hard disk.
On the software front, work was being done to implement the replacement for the aging "user interface" of CP/M, (the Command Console Processor CCP ) with the more modern ZCPR.
Finally a replacement for the aging Z80 processor was being developed in the form of an Intel 8086 board, and additional 512K 16 bit memory boards. Such replacements of CPU and memory system components were possible because the Aster CT-80 was designed to use a backplane that was designed to support both 8 and 16 bit processors, and used a modular Eurocard based design with slots to spare for expansion. In theory the system could support the Z80 and the 8086 simultaneously. Plans were formulated to support CP/M-86 and even MS-DOS.
Unfortunately none of these extensions to the system became available because the company folded before any of them could be released.
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