TI-H: Need help with 8-bit sound software/MODEM IDEA!!!

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TI-H: Need help with 8-bit sound software/MODEM IDEA!!!

>Yes, the sound needs to be 8 bit or else it will sound completely 
>horrible.  I think that the best solution would be to use a serial 
>DAC, just like the ones used in most portable CD players.  I can't 
>remember where, but somewhere on the WEB I saw some datasheets for 
>one of these chips.  This would make the sound adapter very simple.
>
>-Ed

The chip I'm using is from MAXIM, and you can get LOTS of FREE SAMPLES 
from them. I got the MAX550B and several other chips. I made my first 
prototype with a 10-bit DAC, so realy we could have done 10-bit sound, 
but that isn't a standard. I finalized the prototype design by switching 
it with the MAX550B, which is a Microwire serial DAC that seems perfect. 
I just need to know if Microwire is a protocol that TI calcs can 
interface with. If it is, then I HAVE a WORKING 8-bit sound generator. I 
want to get someone who's good al link port programming to try 
programming a waveform generator. A full featured waveform generator 
could probably create Sine, triangle, sawtooth, square, and noise 
waveforms, combine 2 or more wave functions and output the 8-bit 
composite wave to the link or SPinTerface port. The DAC would convert it 
to analog data, alowing the 8-bit sound to vbe played through a speaker. 
The sound quality and capabilities could easily reach GameBoy  type 
sound. You could do dizitized sound, but it is so large (5K per each 
second of sound when sampled at 5KHz). Digitizing of 8-bit sound is 
something only expander games should use, and you would want the 
expander to be connected, so for now, I think we should settle on a 
standard piece of AVALIABLE hardware that's simple as possible (one 
chip) and we should have two standards for generating sound. Digitized 
sound output a byte at a time and waveform generated sound that would 
make specific frequencies. There should be a way set up to interface to 
it so you can give the atack, delay, sustain, and decay stuff and simple 
tone generations. I know that the processor can do it because the 
Commodore 128 had only a 1 MHz Z80 in it. It had the physical waveform 
generator, but that can be emulated with those extra 5 MHz we have at 
our disposal. My only concern is the big games like Daedalus. Stuff like 
that use massive compute cycles for graphics and sound would take just 
as much power, so maybe we could make turbo only software that would be 
designed specificly for turboed calcs. 

I just wan't to emphasize the WAVEFORM GENERATION. I think it has been 
skipped over twice. It is like plotting a graph, to the link port, where 
the collumns of the "screen" are each byte of data. The wave increases 
and decreases the value of the byte just as the dots of a screen are 
plotted higer or lower. Digitizing is like taking a picture of that 
graph, saving each individual dot. Dizitizing takes too much memory, but 
the result is almost instant. The waveform generation plots the sound 
out as a function. The obvious advantage is that you simply need an 
equation and a plotting routine to "plot" to the link port. this takes 
extra cycles though, which is the most obvious disadvantage. I want 
somone to evaluate for me what needs to be saved more, cycles or memory. 
I say we should go with Waveform Generation and save memory, at the cost 
of some cycles.

Another idea is an acoustic modem. It would be slow, but you could 
possibly transmit at nearly 5Kbits per second (maybe) by transmitting 
data converted to sound. You would have to add an ADC to the circuit and 
alternate them or something, but at least you're transmitting analog 
sound rather than stuck with useles digital data. Besides, what game 
will need more than 625 bytes per second? You could plug a device into 
the phone or use an electromagnetic pickup so the sound doesn't get 
interference. you would dial the number and wait for the other pesom to 
pick up and attach the calcs. Start sending data and you're ready. What 
about that AND, OR, XOR stuff. Would it be possible to use those to join 
a digital signal with a carier sine wave. It would all be done with 
software, but software emulation may someday lead to a suggestion for a 
hardware solution???

Who knows???

Please respond!!!   (;

Richard Piotter

e-mail: richfiles@hotmail.com

home page: <A 
HREF="http://www.geocities.com/SiliconValley/Lakes/5081/Richfiles.html">The 
Richfiles</A>

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