I finally achieved something I have wanted to do for 30 years - give the Aquarius programmable characters and true bitmap graphics! (perhaps if it had this built in originally, it might not have bombed so badly when launched back in 1983).
My first goal was to just replace the character ROM with a 2k static RAM and multiplexer circuit, allowing individual character patterns to be redefined if desired. This worked well, but then I realized that with just one more logic chip I could boost the number of programmable characters from 256 to 1024 (4 banks of 256). By selecting each bank of characters in a different horizontal section of the screen, I could create a 320x200 true bitmap graphics mode.
Below are a few monochrome bitmap images displayed on my Aquarius. To process these and get them into my machine I used a hodgepodge of various software tools:-
- Corel Photo-Paint 7: crop, scale, reduce colors, save as 320x200 BMP image.
- BMPAQV41 by Moonsweeper: modified to convert BMP file into character patterns and save as asm include file.
- Zmac macro assembler: convert asm source to binary file.
- AQ_tapeldprep: convert binary file to CAQ tape format for use with McNamara & Dubois BASIC loader.
- CAQ2WAV: convert CAQ file to WAV audio.
- VLC media player: play WAV file through PC sound card to Aquarius tape port.
And here is a YouTube video showing the above image loading from tape. The psychedelic moire effect is caused by interaction between my cellphone camera and the monitor screen. I think it enhances the video - makes it look like it was produced back in the 1970's
Of course no existing software can make use of this enhancement - so was it worth doing, or is it just a pointless hack? What do you think?