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The next thing I wanted to do for the game was to come up with some really neat sound effects. Since the sound chip on the /4A was only capable of generating square waves, I wanted to use the speech chip. The speech chip operates by using a model of the human vocal tract, and I reasoned that if people could make really strange noises, then so could the speech module. After studying the speech chip specifications, I made an important discovery: the speech chip didn't need new data very often (it sure helps to understand hardware when writing software). This fact could be combined with one of the new feature in the 99/4A software architecture -- the user video interrupt. The net effect of this combination was that the speech chip could be used while the game was going on. Then I went to the software folks with my discovery, they told me that "you couldn't do that." Only after I showed them did they believe.
I created the asteroids in [[Parsec]] in TI Logo. I wrote a small Logo program to animate them, and iterated the shapes until they were satisfactory to me. Then I wrote an assembly program to convert the asteroid bitmap from the binary TI Logo data file to ASCII data statements for use with the 9900 assembler.
All of the above programming was done on the 99/4A using the Editor/Assembler package. EVERYTHING I wrote for the 99/4A was written using the Editor/Assembler cartridge. I liked it much better this way, because I could work at home, and I could fi the /4A system if it went down, unlike the 990 minicomputers.
As [[Jim Darmis:Jim]] continued to progress with [[Parsec]] ((we brainstormed on ideas, but he did most of the game flow implementation), the Mini Memory cartridge was developed. However, there was no software available to make it do anything useful. So, I suggested that this would be a great too, for letting people experiment with assembly language without having to have any peripherals other than a cassette recorder. The Line-by-Line Assembler was a derivative of the code used in a TI single board computer which had been developed for microprocessor courses at the university level. This single board computer was called the University Board (model no. 990/189). When I returned to school after my first coop session, I had borrowed one of these from TI and it was an excellent learning tool for me so I assume a similar capability on the /4A would also be good.
[[Category:Software programmer]]
